Optical Module and Network Device

Abstract

An optical module includes a first multiplexer/demultiplexer and an optical receiver. The first multiplexer/demultiplexer is configured to receive a first optical signal from the second network device, separate a second optical signal having a first wavelength from the first optical signal, and transfer the second optical signal to the optical receiver. The first multiplexer/demultiplexer is further configured to transfer a third optical signal that is separated from the first optical signal and that has a wavelength other than the first wavelength to the third network device. The optical receiver is configured to receive the second optical signal.

Claims

1. An access ring network, comprising: a first network device implemented as an access point and comprising an optical module: a second network device optically coupled to the first network device: and a third network device optically coupled to the first network device, wherein the optical module comprises: a first multiplexer/demultiplexer configured to: receive a first optical signal from the second network device; separate a second optical signal from the first optical signal, wherein the second optical signal has a first wavelength; transfer the second optical signal; separate a third optical signal from the first optical signal, wherein the third optical signal has a wavelength other than the first wavelength; and transfer the third optical signal to the third network device; an optical receiver coupled to the first multiplexer/demultiplexer and configured to receive the second optical signal from the first multiplexer/demultiplexer, wherein an operating wavelength of the optical receiver is the first wavelength; and a second multiplexer/demultiplexer configured to: receive a fourth optical signal comprising the first wavelength; receive a fifth optical signal from the third network device; combine the fourth optical signal and the fifth optical signal into a sixth optical signal; and send the sixth optical a to the second network device.

2. The access ring network of claim 1, wherein the optical module further comprises an optical transmitter coupled to the second multiplexer/demultiplexer and configured to transmit the fourth optical signal to the second multiplexer/demultiplexer.

3. The access ring network of claim 1, wherein the optical module further comprises an optical transmitter coupled to the second multiplexer/demultiplexer and configured to transmit a seventh optical signal to the first multiplexer/demultiplexer, wherein the seventh optical signal has a second wavelength, and wherein the first multiplexer/demultiplexer is further configured to: combine an eighth optical signal from the third network device and the seventh optical signal into a ninth optical signal; and send the ninth optical signal to the second network device.

4. An access ring network, comprising: a first network device implemented as an access point and comprising an optical module, wherein the first network device is configured to receive a first optical signal comprising a first wavelength; a second network device optically coupled to the first network device and configured to transmit a second optical signal, and a third network device optically coupled o the first network device, wherein the optical module comprises: a first multiplexer/demultiplexer configured to: receive the first optical signal; combine the second optical signal and the first optical signal into a third optical signal; and send the third optical signal to the third network device; and an optical transmitter configured to transmit the first signal to the first multiplexer/demultiplexer.

5. An optical system applied to a convergence point in an access ring, comprising: N access points, wherein each of the N access points comprises an optical transmitter comprising a different operating wavelength; N optical modules in a one-to-one correspondence with the N access points, wherein an Nth optical module of the N optical modules comprises an optical receiver, wherein an Nth access point of the N access points comprises an optical transmitter, wherein an operating wavelength of the optical receiver is the same as an operating wavelength of the optical transmitters, wherein N is a positive integer greater than 1, and wherein a first optical module of the N optical modules comprises: a first multiplexer/demultiplexer configured to: receive a first optical signal; separate a second optical signal from the first optical signal, wherein the second optical signal has a first wavelength, and wherein the second optical signal is from a first access point of the N access points; transfer the second optical signal; and transfer a third optical signal to a second optical module in N optical modules that is optically coupled to the first optical module, and wherein the third signals an optical signal that is separated from the first optical signal and that has a wavelength other than the first wavelength; and an optical receiver coupled to the first multiplexer/demultiplexer, wherein an operating wavelength of the optical receiver is the first wavelength, and wherein the optical receiver is configured to receive the second optical signal from the first multiplexer/demultiplexer.

6. The optical system of claim 5, wherein the first optical module further comprises: a second optical transmitter configured to transmit a fourth optical signal; and a second multiplexer/demultiplexer coupled to the second optical transmitter and configured to: receive the fourth optical signal comprising the first wavelength from the second optical transmitter; combine a fifth optical signal from the second optical module and the fourth optical signal into a sixth optical signal, and send the sixth optical signal.

7. The optical system according of claim 5, wherein the first optical module further comprises as second optical transmitter,wherein the second optical transmitter is configured to transmit a seventh optical signal to the first multiplexer/demultiplexer, wherein the seventh optical signal has a second wavelength, and wherein the first multiplexer/demultiplexer is further configured to: combine an eighth optical signal from the second optical module and the seventh optical signal into a ninth optical signal; and send the ninth optical signal.

8. The access ring network of claim 1, wherein the optical is a receiver optical subassembly (ROSA).

9. The access ring network of claim 1, wherein the first multiplexer/demultiplexer is further configured to: transmit the second optical signal with the first wavelength; and reflect all other wavelengths.

10. The access ring network of claim 1, wherein the first multiplexer/demultiplexer is further configured to: transmit the third optical signal with the wavelength other than the first wavelength; and reflect all other wavelengths.

11. The access ring network of claim 10, wherein the first multiplexer/demultiplexer is a wavelength-division multiplexer (WDM).

12. The access ring network of claim 1, further comprising a signal processor coupled to the optical receiver, the first multiplexer/demultiplexer, and the second multiplexer/demultiplexer, wherein the signal processor is configured to: combine at least two electrical signals into a first electrical signal; and send the first electrical signal to an optical transmitter, wherein the optical transmitter is a transmitter optical subassembly (TOSA), and wherein the optical module comprises the optical transmitter.

13. The access ring network of claim 12, further comprising a laser diode driver (DRV) coupled to the signal processor and configured to drive the optical transmitter.

14. The optical system of claim 5, wherein signal transmission of at least one of the first optical signal, he second optical signal, or the third optical signal is a pulse-amplitude modulation (PAM) signal.

15. The optical system of claim 5, wherein the optical receiver is a receiver optical subassembly (ROSA).

16. The optical system of claim 5, wherein the first multiplexer/demultiplexer is further configured to: transmit the second optical signal with the first wavelength; and reflect all other wavelengths.

17. The optical system of claim 5, wherein the first multiplexer/demultiplexer is further configured to: transmit the third optical signal with the wavelength other than the first wavelength, and reflect all other wavelengths.

18. The optical system of claim 17, wherein the first multiplexer/demultiplexer is a wavelength-division multiplexer (WDM).

19. The optical system of claim 5, further comprising a signal processor coupled to the optical receiver, wherein the signal processor is configured to: combine at least two electrical signals into a first electrical signal; and send the first electrical signal to the optical transmitter, wherein the optical transmitter is a transmitter optical subassembly (TOSA), and wherein the optical module comprises the optical transmitter.

20. The optical system of claim 19, further comprising a laser diode driver (DRV) coupled to the signal processor and configured to drive the optical transmitter.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0034] FIG. 1 is an architectural diagram of a metropolitan area network according to an embodiment of this application.

[0035] FIG. 2 is a schematic structural diagram of an access ring according to an embodiment of this application.

[0036] FIG. 3 is a schematic structural diagram of a two-fiber unidirectional access ring according to an embodiment of this application.

[0037] FIG. 4 is a schematic structural diagram of an optical module applied to an access point according to an embodiment of this application.

[0038] FIG. 5A is a schematic diagram of filtering of a second multiplexer/demultiplexer according to an embodiment of this application.

[0039] FIG. 5B is a schematic diagram of filtering of a first multiplexer/demultiplexer according to an embodiment of this application.

[0040] FIG. 6 is a schematic structural diagram of an optical system applied to a convergence point according to an embodiment of this application.

[0041] FIG. 7 is a schematic structural diagram of an access point 2 according to an embodiment of this application.

[0042] FIG. 8 is a schematic structural diagram of a single-fiber unidirectional access ring according to an embodiment of this application.

[0043] FIG. 9A is a schematic structural diagram of an optical module applied to an access point according to an embodiment of this application.

[0044] FIG. 9B is a schematic structural diagram of a fifth multiplexer/demultiplexer according to an embodiment of this application.

[0045] FIG. 10 is a schematic structural diagram of an optical system applied to a convergence point according to an embodiment of this application.

[0046] FIG. 11 is a schematic structural diagram of an access point 2 according to an embodiment of this application.

DETAILED DESCRIPTION OF EMBODIMENTS

[0047] FIG. 1 is an architectural diagram of a metropolitan area network according to an embodiment of this application. The metropolitan area network mainly includes three layers an access layer, a convergence layer, and a core layer. The core layer mainly bears and transmits high-bandwidth service and completes interconnection and interworking with an existing network. The existing network may include an asynchronous transfer mode (ATM) network, a digital data network (DDN), an Internet Protocol (IP) network, and the like. A main function of the convergence layer is to provide convergence and distribution processing of user service data for a service access node, and implement service class classification of services. The access layer performs bandwidth and service allocation using a plurality of access technologies, and implements user access, and an access layer device implements multiplexing and transmission of a plurality of services.

[0048] During networking, the access layer and the convergence layer still use a ring structure to construct a system. The access layer uses a gigabit Ethernet (GE) rate, and the convergence layer uses a 10-GE rate to construct a ring, and uses a ring structure including two convergence nodes to prevent a single node failure risk of a convergence point and a backbone node. Each backbone layer node is directly connected to a related core layer node at a backbone layer using a GE or 10-GE link provided by an optical transport network (OTN). The following provides descriptions using an example in which networking is performed using a PTN device. A person skilled in the art may understand that this application is not limited to networking based on a PTN device, for example, any network device such as a router may be alternatively used for networking, and this is not specifically limited in this application.

[0049] To increase a network bandwidth of an access ring, currently, a manner of increasing a processing bandwidth of an optical module in each PTN device (an access point or a convergence point) in the access ring is generally used, as shown in FIG. 2. However, if a processing bandwidth of each optical module is upgraded from 10 gigabits (G) to 100 G, costs increase by 30 to 50 times, leading to a great increase in overall costs of the PTN device. For example, in FIG. 2, when a PTN device 2 receives an optical signal sent by a connected PTN device 1, an optical module in the PTN device 2 generally converts all received signals into electrical signals, after converting the signals into the electrical signals, determines a signal that is to be processed by the PTN device 2 and a signal that is not to be processed by the PTN device 2, and then converts the signal that is not to be processed by the PTN device 2 into a corresponding optical signal, and then forwards the optical signal to a PTN device 3 connected to the PTN device 2. It can be learned that in this manner, a relatively large quantity of processing resources of the PTN device are occupied, and consequently, usage of a processing bandwidth of the optical module in the PTN device is relatively high. Even if a bandwidth of each optical module is upgraded to 100 G, because a signal needing to be forwarded occupies a bandwidth of the optical module in the PTN device, an actual bandwidth of each optical module cannot reach 100 G. If an optical module in each PTN device processes only uplink and downlink signals needed by the local PTN device, does not process a signal needing to be forwarded to another access point or a convergence point, and directly forwards the signal, a pressure of the PTN device in the access ring is reduced to some extent, power consumption of the PTN device is reduced, and usage of a bandwidth of the optical module is reduced such that the optical module can have a higher bandwidth to process the signal needed by the local PTN device, and an actual processing bandwidth of the PTN device is increased.

[0050] Based on this, an embodiment of this application provides an optical module and a network device. An optical module in an access ring processes only uplink and downlink signals needed by the optical module, does not process a signal needing to be forwarded to another PTN device, and directly forwards the signal to the other PTN device using a multiplexer/demultiplexer, thereby reducing a processing pressure of the optical module, and effectively increasing a processing bandwidth of the optical module.

[0051] In addition, it should be noted that in the descriptions of this application, the network device may be any device that can use an optical module in the access ring, for example, the foregoing PTN device or an OTN device. The network device may be an access point in the access ring, or may be a convergence point. A plurality in the descriptions of this application means at least two. In the descriptions of this application, terms such as first and second are merely used for distinguishing, but should not be understood as indicating or implying relative importance, or should not be understood as indicating or implying a sequence.

[0052] In this embodiment of this application, the access ring may support bidirectional transmission, which may be specifically two-fiber unidirectional transmission or single-fiber bidirectional transmission. The two-fiber unidirectional transmission means that any two network devices in the access ring are connected using two fibers, and directions of transmitting optical signals using the two fibers are opposite. The single-fiber bidirectional transmission means that any two network devices in the access ring are connected using one fiber, and the fiber can be used to transmit optical signals in two directions.

[0053] FIG. 3 is a schematic structural diagram of an access ring according to an embodiment of this application. The access ring uses a two-fiber unidirectional manner. The access ring may include N access points and a convergence point. FIG. 3 merely shows an example, and does not specifically limit quantities of access points and convergence points included in the access ring. Descriptions are provided herein using an example in which the access ring includes three access points. The access points included in the access ring are respectively an access point 1, an access point 2, and an access point 3. The access point 2 is connected to both the access point 1 and the access point 3 using fibers, and the convergence point is connected to both the access point 1 and the access point 3 using fibers.

[0054] The following provides descriptions using a structure of the access point 2 as an example. For the other access points, refer to the structure of the access point 2. The access point 2 includes an optical module 400. As shown in FIG. 4, the optical module 400 includes a first multiplexer/demultiplexer 4041, a second multiplexer/demultiplexer 4042, an optical transmitter 4031, and an optical receiver 4032. Operating wavelengths of optical modules included in different access points are different. An operating wavelength of the optical module 400 is a wavelength used by the optical transmitter in the optical module 400 to transmit an optical signal (namely, an operating wavelength of the optical transmitter), and a wavelength used by the optical receiver to receive an optical signal (namely, an operating wavelength of the optical receiver). Operating wavelengths of an optical transmitter and an optical receiver in a same optical module may be the same or may be different. This embodiment is described using an example in which operating wavelengths of an optical transmitter and an optical receiver in a same optical module are the same. The operating wavelength of the optical module included in the access point 1 is 1, an operating wavelength of an optical module included in the access point 2 is 2, and an operating wavelength of the optical module included in the access point 3 is 3.

[0055] The first multiplexer/demultiplexer 4041 receives an optical signal 1 from the access point 1, and then separates an optical signal 2 and an optical signal 3 from the optical signal 1, where a wavelength of the optical signal 2 is 2, and the optical signal 3 is an optical signal having a wavelength other than the wavelength 2 in the optical signal 1.

[0056] The first multiplexer/demultiplexer 4041 transfers the optical signal 2 to the optical receiver 4032, and transfers the optical signal 3 to the access point 3 such that the optical receiver 4032 receives the optical signal 1, where an operating wavelength of the optical receiver 4032 is 2.

[0057] The optical transmitter 4031 is configured to transmit an optical signal 4 to the second multiplexer/demultiplexer 4042, where an operating wavelength of the optical transmitter 4031 is 2, that is, a wavelength of the optical signal 4 is also 2.

[0058] The second multiplexer/demultiplexer 4042 is configured to receive an optical signal 5 from the access point 3, combine the optical signal 5 and the optical signal 4 into an optical signal 6, and send the optical signal 6 to the access point 1.

[0059] Optionally, the optical transmitter 4031 may be a transmitter optical subassembly (TOSA) 4031, and the optical receiver 4032 may be a receiver optical subassembly (ROSA) 4032.

[0060] Optionally, the optical module 400 may further include a first optical input interface 4011, a first optical output interface 4012, a second optical input interface 4021, and a second optical output interface 4022.

[0061] The first multiplexer/demultiplexer 4041 and the second multiplexer/demultiplexer 4042 each may transmit an optical signal having a wavelength and reflect an optical signal having the other wavelength, or reflect an optical signal having a wavelength and transmit an optical signal having the other wavelength, for example, may be a WDM. This embodiment of this application is described using an example in which the first multiplexer/demultiplexer 4041 and the second multiplexer/demultiplexer 4042 each may transmit an optical signal having a wavelength and reflect an optical signal having the other wavelength.

[0062] Optionally, the first multiplexer/demultiplexer 4041 may include two optical interfaces an optical interface 21 and an optical interface 22. The optical interface 21 may be used as the second optical output interface 4022 of the optical module, and the optical interface 22 may be used as the first optical input interface 4011.

[0063] Optionally, the first multiplexer/demultiplexer 4041 may further include an optical interface 23. The optical interface 23 is configured to transmit, to the first multiplexer/demultiplexer 4041, the optical signal 4 that is sent by the TOSA 4031 and that has the wavelength 2, as shown in FIG. 5B. Likewise, the second multiplexer/demultiplexer 4042 may include two optical interfaces an optical interface 11, and an optical interface 12. The optical interface 11 may be used as the first optical output interface 4012 of the optical module, and the optical interface 12 may be used as the second optical input interface 4021. Optionally, the second multiplexer/demultiplexer 4042 may further include an optical interface 13. The second multiplexer/demultiplexer 4042 transmits, through the optical interface 13, the optical signal 1 having the wavelength 2 to the ROSA 4032, as shown in FIG. 5A.

[0064] The TOSA 4031 transmits the optical signal 4 having the wavelength 2 to the second multiplexer/demultiplexer 4042. The second multiplexer/demultiplexer 4042 not only receives the optical signal 4 transmitted by the TOSA 4031, but also receives the optical signal 5 that is sent by the access point 3 through the second optical input interface 4021 and that has a wavelength other than the wavelength 2 such that the second multiplexer/demultiplexer 4042 combines the optical signal 4 transmitted by the TOSA 4031 and the optical signal 5 into the optical signal 6, and then sends the optical signal 6 to the access point 1 through the first optical output interface 4012. Referring to FIG. 4, a solid line represents the optical signal 4 having the wavelength 2, and a dashed line represents the optical signal 5. After the optical signal 4 that corresponds to the solid line and that has the wavelength 2 is sent by the TOSA 4031, the optical signal 4 and the optical signal 5 that enters through the second optical input interface 4021 and that corresponds to the dashed line converge at the second multiplexer/demultiplexer 4042, and then are sent through the first optical output interface 4012.

[0065] The first multiplexer/demultiplexer 4041 receives the optical signal 1 that is sent by the access point 1 through the first optical input interface 4011, separates the optical signal 2 having the wavelength 2 from the received optical signal 1, and sends the optical signal 2 to the first multiplexer/demultiplexer 4041, and sends the optical signal 3 having a wavelength other than the wavelength 2 in the received optical signal 1 to the access point 3 in the access ring through the second optical output interface 4022. The ROSA 4032 receives the optical signal 1 sent by the first multiplexer/demultiplexer 4041. In FIG. 4, the optical signal 2 that corresponds to a solid line and that has the wavelength 2 and the optical signal 3 corresponding to the dashed line enter the first multiplexer/demultiplexer 4041 through the first optical input interface 4011, and after the first multiplexer/demultiplexer 4041 performs filtering, the optical signal 2 corresponding to the solid line is sent to the ROSA 4032, and the optical signal 3 corresponding to the dashed line is sent through the second optical output interface 4022.

[0066] The optical module 400 in this embodiment of this application may use a pulse-amplitude modulation (PAM) signal. PAM is a hot signal transmission technology for high speed signal interconnection at a next generation data center, and may be widely applied to electrical signal or optical signal transmission on a 200 G/400 G optical interface. A conventional digital signal mostly is a non-return-to-zero (NRZ) signal. To be specific, a high signal level and a low signal level are used to represent information 1 and 0 of a to-be-transmitted digital logical signal, and 1-bit logical information may be transmitted in each signal symbol period. For a PAM 4 signal, four different signal levels are used for signal transmission, and 2-bit logical information (0, 1, 2, 3) may be represented in each symbol period. Because 2-bit information may be transmitted in each symbol period using the PAM 4 signal, to achieve a same signal transmission capability, a symbol rate of the PAM 4 signal needs to reach only a half of that of the NRZ signal. Therefore, a loss caused by a transmission channel to the PAM 4 signal is greatly reduced. With the development of future technologies, a possibility of performing information transmission using a PAM 8 signal of more levels and even a PAM 16 signal of more levels is not excluded.

[0067] Optionally, the optical module 400 may further include a first signal processor 4033. As shown in FIG. 4, the first signal processor 4033 combines received at least two electrical signals into one first electrical signal, and then sends the combined first electrical signal to the TOSA 4031 such that the TOSA 4031 converts the first electrical signal into an optical signal 4 having the wavelength 2, and sends the optical signal 4 to the second multiplexer/demultiplexer 4042, and the second multiplexer/demultiplexer 4042 sends the optical signal 4 through the first optical output interface 4012. The first signal processor 4033 may be a general purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array or another programmable logic device, a discrete gate or transistor logic device, a discrete hardware component, or the like. In FIG. 4, that the first signal processor 4033 is a DSP 4033 is used as an example.

[0068] The optical module 400 may further include a laser diode driver (DRV) such that the first signal processor 4033 combines the received at least two electrical signals into one electrical signal 1, and then sends the electrical signal 1 to the DRV, and the DRV drives the TOSA 4031 to convert the electrical signal 1 into the optical signal 4 having the wavelength 2.

[0069] The ROSA 4032 is further configured to convert the received optical signal 2 that is sent by the first multiplexer/demultiplexer 4041 and that has the wavelength 2 into an electrical signal 2, and send the electrical signal 2 to the first signal processor 4033. The first signal processor 4033 processes the received electrical signal 2 into at least two electrical signals, and sends the electrical signals.

[0070] The at least two electrical signals may be NRZ signals. The first electrical signal and the second electrical signal may be PAM signals. For example, a line board (for example, an ASIC) in the access point 2 can process two NRZ electrical signals such that the first electrical signal may be a PAM 4 signal.

[0071] In this embodiment of this application, the convergence point may use an optical system including a plurality of the optical modules 400 shown in FIG. 4, and a quantity of the optical modules in the optical system is equal to a quantity of access points in the access ring. In an architecture of the access ring shown in FIG. 3, the convergence point is connected to both the access point 1 and the access point 3. The convergence point may include one or two optical systems. A structure of an optical module included in the optical system is the same as a structure of an optical module included in an access point. The optical system includes three optical modules an optical module 1, an optical module 2, and an optical module 3. The optical module 2 is in optical connection to both the optical module 1 and the optical module 3, and the optical module 1 is connected to the access point 1. FIG. 6 is a schematic structural diagram of the convergence point.

[0072] The optical module 1 corresponds to the access point 1, the optical module 2 corresponds to the access point 2, and the optical module 3 corresponds to the access point 3. Further, an operating wavelength of an optical receiver included in the optical module 1 is the same as an operating wavelength of an optical transmitter included in the access point 1, an operating wavelength of an optical transmitter included in the optical module 1 is the same as an operating wavelength of an optical receiver included in the access point 1, an operating wavelength of an optical receiver included in the optical module 2 is the same as an operating wavelength of an optical transmitter included in the access point 2, an operating wavelength of an optical transmitter included in the optical module 2 is the same as an operating wavelength of an optical receiver included in the access point 2, an operating wavelength of an optical receiver included in the optical module 3 is the same as an operating wavelength of an optical transmitter included in the access point 3, and an operating wavelength of an optical transmitter included in the optical module 3 is the same as an operating wavelength of an optical receiver included in the access point 3. In this embodiment of this application, that operating wavelengths of an optical transmitter and an optical receiver in a same access point are the same is used as an example such that operating wavelengths of an optical receiver and an optical transmitter in a same optical module in the optical system are the same. For convenience of subsequent description, operating wavelengths of an optical transmitter and an optical receiver in an access point are collectively referred to as an operating wavelength of the access point, and operating wavelengths of an optical receiver and an optical transmitter in an optical module in the optical system are collectively referred to as an operating wavelength of the optical module.

[0073] In this embodiment of this application, that the operating wavelength of the access point 1 is 1, the operating wavelength of the access point 2 is 2, and the operating wavelength of the access point 3 is 3 is used as an example such that the operating wavelength of the optical module 1 is 1, the operating wavelength of the optical module 2 is 2, and the operating wavelength of the optical module 3 is 3. Because the optical module 1, the optical module 2, and the optical module 3 are of a same structure, the following provides descriptions using only the optical module 2 as an example, and the optical module 1 and the optical module 3 are not described repeatedly. The optical module 2 includes a third multiplexer/demultiplexer 5041, a fourth multiplexer/demultiplexer 5042, an optical transmitter 5031, and an optical receiver 5032.

[0074] The third multiplexer/demultiplexer 5041 is configured to receive an optical signal 111 from the optical module 1, separate, from the optical signal 111, an optical signal 112 that is from the access point 2, and transfer the optical signal 112 to the optical receiver 5032, where a wavelength of the optical signal 112 is 2.

[0075] The optical receiver 5032 is configured to receive the optical signal 112 sent by the third multiplexer/demultiplexer 5041.

[0076] The third multiplexer/demultiplexer 5041 is further configured to separate an optical signal 113 from the optical signal 111, and send the optical signal 113 to the optical module 3, where the optical signal 113 is an optical signal that is separated from the optical signal 111 and that has a wavelength other than the wavelength 2.

[0077] The optical transmitter 5031 is configured to transmit an optical signal 114 to the fourth multiplexer/demultiplexer 5042, where an operating wavelength of the optical transmitter 5031 is 2, that is, a wavelength of the optical signal 114 is also 2. The optical signal 114 corresponding to the operating wavelength 2 is an optical signal needing to be sent to the access point 2.

[0078] The fourth multiplexer/demultiplexer 5042 is configured to receive an optical signal 115 from the optical module 3, combine the optical signal 115 and the optical signal 114 into an optical signal 116, and send the optical signal 116 to the optical module 1.

[0079] It should be noted that the optical transmitter 5031 may be a TOSA 5031, and the optical receiver 5032 may be an ROSA 5032.

[0080] Optionally, the optical module 2 may further include a first optical input interface 5011, a first optical output interface 5012, a second optical input interface 5021, and a second optical output interface 5022. The first optical input interface 5011 and the first optical output interface 5012 are configured to connect to the optical module 1, and the second optical input interface 5021 and the second optical output interface 5022 are configured to connect to the optical module 3. The first optical input interface 5011 is configured to receive the optical signal 111 sent by the optical module 1, the first optical output interface 5012 is configured to send the optical signal 116 to the optical module 1, the second optical output interface 5022 is configured to send the optical signal 113 to the optical module 3, and the second optical input interface 5021 is configured to receive the optical signal 114 sent by the optical module 3.

[0081] Optionally, the fourth multiplexer/demultiplexer 5042 may include two optical interfaces. The first interface may be used as the first optical output interface 5012 of the optical module, and the second interface may be used as the second optical input interface 5021. Optionally, the fourth multiplexer/demultiplexer 5042 may further include a third optical interface configured to transmit, to the third multiplexer/demultiplexer 5041, the optical signal 114 that is sent by the TOSA 5031 and that has the wavelength 2. Likewise, the third multiplexer/demultiplexer 5041 is similar, and details are not described herein again.

[0082] The third multiplexer/demultiplexer 5041 and the fourth multiplexer/demultiplexer 5042 each may transmit an optical signal having a wavelength and reflect an optical signal having the other wavelength, or reflect an optical signal having a wavelength and transmit an optical signal having the other wavelength, for example, may be a WDM. This embodiment of this application is described using an example in which the third multiplexer/demultiplexer 5041 and the fourth multiplexer/demultiplexer 5042 each may transmit an optical signal having a wavelength and reflect an optical signal having the other wavelength.

[0083] Optionally, the optical module 2 may further include a second signal processor 5033. The second signal processor 5033 combines received at least two electrical signals into one first electrical signal, and then sends the combined first electrical signal to the TOSA 5031 such that the TOSA 5031 converts the first electrical signal into the optical signal 114 having the wavelength 2, and sends the optical signal 114 to the fourth multiplexer/demultiplexer 5042, and the fourth multiplexer/demultiplexer 5042 sends the optical signal 114 through the first optical output interface 5012. The second signal processor 5033 may be a general purpose processor, a DSP, an ASIC, a field programmable gate array or another programmable logic device, a discrete gate or transistor logic device, a discrete hardware component, or the like. In FIG. 6, that the second signal processor 5033 is a DSP 5033 is used as an example.

[0084] The optical module 2 may further include a DRV such that the second signal processor 5033 combines the received at least two electrical signals into one electrical signal 1, and then sends the electrical signal 1 to the DRV, and the DRV drives the TOSA 4031 to convert the electrical signal 1 into the optical signal 114 having the wavelength 2.

[0085] The ROSA 5032 is further configured to convert the received optical signal 112 that is sent by the third multiplexer/demultiplexer 5041 and that has the wavelength 2 into an electrical signal 2, and send the electrical signal 2 to the second signal processor 5033. The second signal processor 5033 processes the received second electrical signal into at least two electrical signals, and sends the electrical signals.

[0086] The at least two electrical signals may be NRZ signals. The electrical signal 1 and the electrical signal 2 may be PAM signals. For example, a line board (for example, an ASIC) in the optical module 2 can process two NRZ electrical signals such that the electrical signal 1 and the electrical signal 2 may be PAM 4 signals.

[0087] In this embodiment of this application, a same access point may include two same optical modules, and a same convergence point may include two same optical systems. Two optical modules of a same access point protect each other, and two optical systems of a same convergence point protect each other. Operating wavelengths of two optical modules in a same access point may be the same or may be different. When operating wavelengths of two optical modules in a same access point are the same, operating wavelengths of two optical systems in a same convergence point are the same. When operating wavelengths of two optical modules in a same access point are different, operating wavelengths of two optical systems in a convergence point are also different. For example, operating wavelengths of two optical modules in the access point 1 are respectively 11 and 12, operating wavelengths of two optical modules in the access point 2 are respectively 21 and 22, and operating wavelengths of two optical modules in the access point 3 are respectively 31 and 32. Then, operating wavelengths of three optical modules included in one optical system in a convergence point are respectively 11, 21, and 31, and operating wavelengths of three optical modules included in the other optical system are respectively 12, 22, and 32.

[0088] That operating wavelengths of two optical modules in a same access point are the same is used as an example. The access point 2 may use two optical modules 400 described in the embodiment corresponding to FIG. 4. FIG. 7 is a schematic structure of the access point 2. For convenience of subsequent description, the first optical input interface 4011 and the first optical output interface 4012 in the optical module 400 may be referred to as network ports, and the second optical input interface 4021 and the second optical output interface 4022 may be referred to as cascade ports such that when the two optical modules 400 are connected using a fiber, the two optical modules 400 are connected through cascade ports. In other words, a cascade port of one optical module 400 is correspondingly connected to a cascade port of the other optical module, and network ports of the two optical modules 400 are configured to respectively connect to the access point 1 and the access point 3.

[0089] The access point 2 further includes two line boards, and the line boards are configured to perform signal processing on signals output by the optical modules 400 or on signals to be input to the optical modules 400. For example, the line boards are ASICs shown in FIG. 7. Different optical modules are connected to different line boards such that east and west directions of the access ring protect each other, and when any node fails, the other node may be used as a standby node and continues to work. The nodes herein include one optical module 400 and one line board.

[0090] When an access point uses the structure shown in FIG. 7, a convergence point may include two optical systems shown in FIG. 6.

[0091] FIG. 8 is a schematic structural diagram of another access ring according to an embodiment of this application. The access ring uses a single-fiber bidirectional manner. The access ring may include N access points and a convergence point. FIG. 8 merely shows an example, and does not specifically limit quantities of access points and convergence points included in the access ring. Descriptions are provided herein using an example in which the access ring includes three access points. The access points included in the access ring are respectively an access point 1, an access point 2, and an access point 3. The access point 2 is connected to both the access point 1 and the access point 3 using fibers, and the convergence point is connected to both the access point 1 and the access point 3 using fibers. The following provides descriptions using a structure of the access point 2 as an example. For the other access points, refer to the structure of the access point 2. The access point 2 includes an optical module 600. As shown in FIG. 9A, the optical module 600 includes a fifth multiplexer/demultiplexer 604, an optical transmitter 6031, and an optical receiver 6032. It should be noted that an operating wavelength of the optical transmitter 6031 is different from an operating wavelength of the optical receiver 6032. Operating wavelengths of optical modules included in different access points are different. For example, operating wavelengths of optical modules in the access point 1 are 110 and 120, operating wavelengths of optical modules in the access point 2 are respectively 210 and 220, and operating wavelengths of optical modules in the access point 3 are respectively 310 and 320.

[0092] The fifth multiplexer/demultiplexer 604 includes two optical filters a first optical filter 6041 and a second optical filter 6042, as shown in FIG. 9B. The first optical filter 6041 may be configured to transmit optical signals having the two wavelengths (210 and 220), and reflect optical signals having wavelengths other than the wavelengths 210 and 220, or may be configured to reflect optical signals having the two wavelengths, and transmit optical signals having wavelengths other than the two wavelengths, and may be specifically a WDM. The second optical filter 6042 can distinguish between the optical signals having the wavelengths 210 and 220. For example, the second optical filter 6042 reflects the optical signal having the wavelength 210, and transmits the optical signal having the wavelength 220, or reflects the optical signal having the wavelength 220, and transmits the optical signal having the wavelength 210. That the operating wavelength of the optical receiver 6032 is 210, and the operating wavelength of the optical transmitter 6031 is 220 is used as an example herein. It should be noted that the optical transmitter 6031 may be a TOSA 6031, and the optical receiver 6032 may be an ROSA 6032.

[0093] In this embodiment, the fifth multiplexer/demultiplexer 604 filters out, from an optical signal 211 that is from the access point 1 and through two-level optical filtering, an optical signal 212 having a wavelength that can be received by the optical receiver 6032, transfers the optical signal 212 to the optical receiver 6032, and transfers an optical signal 213 that is filtered out and that has a wavelength other than the wavelengths 210 and 220 to the access point 3. The wavelength of the optical signal 212 is 210. The optical transmitter 6031 transmits the optical signal 214 having the wavelength 220, and the fifth multiplexer/demultiplexer 604 combines an optical signal 215 from the access point 3 and the received optical signal 214 into an optical signal 216, and then transfers the optical signal 216 to the access point 1. The optical signal 215 does not include optical signals having the wavelengths 210 and 220. The optical module 600 may further include two interfaces a first optical interface 601 and a second optical interface 602, which are configured to respectively connect to the access point 1 and the access point 3.

[0094] Referring to FIG. 9A, a solid line 1 represents an optical signal having the wavelength 210, a solid line 2 represents the optical signal having the wavelength 220, and the other dashed lines represent optical signals having the other wavelengths. After the optical signal 214 that corresponds to the solid line 2 and that has the wavelength 220 is sent through the TOSA 6031, optical signals 215 that are from the access point 2, that correspond to the dashed lines, and that have the other wavelengths and the optical signal 214 enter through the second optical interface 602, and after the signals are combined into the optical signal 216 at the fifth multiplexer/demultiplexer 604, the optical signal 216 is sent to the access point 1 through the first optical interface 601.

[0095] The fifth multiplexer/demultiplexer 604 receives the optical signal 211 that is sent by the access point 1 through the first optical interface 601, separates the optical signal 212 having the wavelength 210 from the optical signal 211 received from the first optical interface 601, and sends the optical signal 212 to the ROSA 6032, filters out, from the optical signal 211 received from the first optical interface 401, the optical signal 213 having the wavelength other than the wavelengths 210 and 220, and sends the optical signal 213 to the access point 3 through the second optical interface 602. In FIG. 9A, the optical signal that corresponds to the solid line 1 and that has the wavelength 210 and the optical signals that correspond to the dashed lines and that have the other wavelengths enter the fifth multiplexer/demultiplexer 604 through the first optical interface 401, and after the fifth multiplexer/demultiplexer 604 performs filtering, the optical signal 212 corresponding to the solid line 1 is sent to the ROSA 6032, and the optical signals 213 that correspond to the dashed lines and that have the other wavelength is sent through the second optical interface 402.

[0096] Optionally, the optical module 600 may further include a third signal processor 6033. The third signal processor 6033 may be a general purpose processor, a DSP, an ASIC, a field programmable gate array or another programmable logic device, a discrete gate or transistor logic device, a discrete hardware component, or the like. In FIG. 9A, that the third signal processor 6033 is a DSP 6033 is used as an example.

[0097] The third signal processor 6033 combines received at least two electrical signals into one electrical signal 1, and then sends the combined electrical signal 1 to the TOSA 6031. The TOSA 6031 converts the received electrical signal 1 sent by the DSP 6033 into the optical signal 214 having the wavelength 220. The ROSA 6032 converts the received optical signal 212 that is sent by the fifth multiplexer/demultiplexer 604 and that has the wavelength 210 into an electrical signal 2, and sends the electrical signal 2 to the third signal processor 6033. The third signal processor 6033 is further configured to process the received electrical signal 2 into at least two electrical signals, and send the electrical signals.

[0098] The at least two electrical signals may be NRZ signals. The electrical signal 1 and the electrical signal 2 may be PAM signals. For example, a line board in the access point 2 can process two NRZ electrical signals such that the electrical signal 1 and the electrical signal 2 may be PAM 4 signals.

[0099] In this embodiment of this application, the convergence point may use an optical system including a plurality of the optical modules 600 shown in FIG. 9A, and a quantity of the optical modules in the optical system is equal to a quantity of access points in the access ring. In an architecture of the access ring shown in FIG. 8, the convergence point is connected to both the access point 1 and the access point 3. The convergence point may include one or two optical systems. A structure of an optical module included in the optical system is the same as a structure of an optical module included in an access point. The optical system includes three optical modules an optical module 1, an optical module 2, and an optical module 3. The optical module 2 is in optical connection to the optical module 1 and the optical module 3, and the optical module 1 is connected to the access point 1. FIG. 10 is a schematic structural diagram of the convergence point. The optical module 1 corresponds to the access point 1, the optical module 2 corresponds to the access point 2, and the optical module 3 corresponds to the access point 3. An operating wavelength of an optical receiver in an optical module in the access point 1 is 110, and then an operating wavelength of an optical transmitter in the optical module 1 in the optical system is 110. An operating wavelength of an optical transmitter in the optical module in the access point 1 is 120, and then an operating wavelength of an optical receiver in the optical module 1 in the optical system is 120. An operating wavelength of an optical receiver in an optical module in the access point 2 is 210, and then an operating wavelength of an optical transmitter in the optical module 2 in the optical system is 210. An operating wavelength of an optical transmitter in the optical module in the access point 2 is 220, and then an operating wavelength of an optical receiver in the optical module 2 in the optical system is 220. An operating wavelength of an optical receiver in an optical module in the access point 3 is 310, and then an operating wavelength of an optical transmitter in the optical module 3 in the optical system is 310. An operating wavelength of an optical transmitter in the optical module in the access point 3 is 320, and then an operating wavelength of an optical receiver in the optical module 3 in the optical system is 320. Because the optical module 1, the optical module 2, and the optical module 3 are of a same structure, the following provides descriptions using only the optical module 2 as an example, and the optical module 1 and the optical module 3 are not described repeatedly. The optical module 2 includes a sixth multiplexer/demultiplexer 704, an optical transmitter 7031, and an optical receiver 7032.

[0100] The sixth multiplexer/demultiplexer 704 includes two optical filters a third optical filter 7041 and a fourth optical filter 7042.

[0101] It should be noted that an operating wavelength of the optical transmitter 7031 is different from an operating wavelength of the optical receiver 7032. Operating wavelengths of optical modules included in different access points are different. For example, operating wavelengths of optical modules in the access point 1 are 110 and 120, operating wavelengths of optical modules in the access point 2 are respectively 210 and 220, and operating wavelengths of optical modules in the access point 3 are respectively 310 and 320.

[0102] The third optical filter 7041 may be configured to transmit optical signals having the two wavelengths (210 and 220), and reflect an optical signal having a wavelength other than the wavelengths 210 and 220, or may be configured to reflect optical signals having the two wavelengths, and transmit an optical signal having a wavelength other than the two wavelengths, and may be specifically a WDM. The fourth optical filter 7042 can distinguish between the optical signals having the wavelengths 210 and 220. For example, the fourth optical filter 7042 reflects the optical signal having the wavelength 210, and transmits the optical signal having the wavelength 220, or reflects the optical signal having the wavelength 220, and transmits the optical signal having the wavelength 210. That the operating wavelength of the optical receiver 7032 is 220, and the operating wavelength of the optical transmitter 7031 is 210 is used as an example. It should be noted that the optical transmitter 7031 may be a TOSA 7031, and the optical receiver 7032 may be an ROSA 7032.

[0103] In this embodiment, the sixth multiplexer/demultiplexer 704 filters out, from an optical signal 31 that is from the optical module 1 and through two-level optical filtering, an optical signal 32 having a wavelength that can be received by the optical receiver 7032, transfers the optical signal 32 to the optical receiver 7032, and transfers an optical signal 33 that is filtered out and that has a wavelength other than the wavelengths 210 and 220 to the optical module 3. The wavelength of the optical signal 32 is 220. The optical transmitter 7031 transmits an optical signal 34 having the wavelength 210, and the sixth multiplexer/demultiplexer 704 combines an optical signal 35 from the optical module 3 and the received optical signal 34 into an optical signal 36, and then transfers the optical signal 36 to the optical module 1. The optical signal 35 does not include optical signals having the wavelengths 210 and 220. The optical module may further include two interfaces a third optical interface 701 and a fourth optical interface 702, which are configured to respectively connect to the access point 1 and the access point 3.

[0104] Optionally, the optical module 2 may further include a fourth signal processor 7033. The fourth signal processor 7033 combines received at least two electrical signals into one electrical signal 1, and then sends the combined electrical signal 1 to the TOSA 7031 such that the TOSA 7031 converts the electrical signal 1 into the optical signal 34 having the wavelength 210, and sends the optical signal 34 to the sixth multiplexer/demultiplexer 704, and the sixth multiplexer/demultiplexer 704 sends the optical signal 34 through the third optical interface 701. The second signal processor 7033 may be a general purpose processor, a DSP, an ASIC, a field programmable gate array or another programmable logic device, a discrete gate or transistor logic device, a discrete hardware component, or the like. In FIG. 10 that the fourth signal processor 7033 is a DSP 7033 is used as an example.

[0105] The optical module may further include a DRV such that the fourth signal processor 7033 combines the received at least two electrical signals into one electrical signal 1, and then sends the electrical signal 1 to the DRV, and the DRV drives the TOSA 7031 to convert the electrical signal 1 into the optical signal 34 having the wavelength 210.

[0106] The ROSA 7032 is further configured to convert the received optical signal 32 that is sent by the sixth multiplexer/demultiplexer 704 and that has the wavelength 220 into an electrical signal 2, and send the electrical signal 2 to the fourth signal processor 7033. The fourth signal processor 7033 processes the received electrical signal 2 into at least two electrical signals, and sends the electrical signals.

[0107] The at least two electrical signals may be NRZ signals. The electrical signal 1 and the second electrical signal 2 may be PAM signals. For example, a line board (for example, an ASIC) in the optical module 2 can process two NRZ electrical signals such that the electrical signal 1 and the electrical signal 2 may be PAM 4 signals.

[0108] In this embodiment of this application, a same access point may include two same optical modules, and a same convergence point includes two same optical systems. Two optical modules of a same access point protect each other, and two optical systems of a same convergence point protect each other. Operating wavelengths of two optical modules in a same access point may be the same or may be different. When operating wavelengths of two optical modules in a same access point are the same, operating wavelengths of two optical systems in the same convergence point are the same. When operating wavelengths of two optical modules in a same access point are different, operating wavelengths of two optical systems in a convergence point are also different.

[0109] That operating wavelengths of two optical modules in a same access point are the same is used as an example. The access point 2 may use two optical modules described in the embodiment corresponding to FIG. 9A, as shown in FIG. 11. For convenience of subsequent description, the first optical interfaces 601 in the optical modules may be referred to as network ports, and the second optical interfaces 602 may be referred to as cascade ports such that when the two optical modules are connected using a fiber, the two optical modules are connected through cascade ports. In other words, a cascade port of one optical module is correspondingly connected to a cascade port of the other optical module using a fiber, and the network ports of the two optical modules are configured to respectively connect to the access point 1 and the access point 3.

[0110] The access point 2 further includes two line boards, and the line boards are configured to perform signal processing on signals output by the optical modules or on signals to be input to the optical modules. For example, the line boards are (ASICs shown in FIG. 11. Different optical modules are connected to different line boards such that east and west directions of the access ring protect each other, and when any node fails, the other node may be used as a standby node and continues to work. The nodes herein include one optical module and one line board.

[0111] When an access point uses the structure shown in FIG. 11, a convergence point may include two optical systems shown in FIG. 10.

[0112] The following describes optical power in a solution used in the embodiments of this application. For example, an optical module in any embodiment of this application is a 50 GE optical module, a used TOSA is a directly modulated laser (DML) TOSA, and an ROSA is a photodiode PIN ROSA. Light out-coupling efficiency of the DML TOSA is greater than 0 decibel milliwatts (dBm), and receiver sensitivity of the PIN ROSA is 13 dBm such that an optical power budget is 13 dBm. A loss of a 20 kilometer (km) fiber is 20 km*0.275 decibel (dB)/km=5.5 dB, a maximum loss of optical layer penetration is 5 dB, and a 2.5 dB fiber connector loss is reserved. Based on this, an optical module constructed using the DML TOSA and the PIN ROSA and the solution provided in this application can meet a requirement for a 20 km access ring. When an optical module is a 50 GE optical module, a signal processor described in any embodiment is configured to process two 25 G electrical signals, and a Baud rate is 25 G. When a length of an access ring is less than or equal to 20 km, dispersion compensation does not need to be considered. Based on this, the embodiments of this application may be applied to a PTN-based metropolitan area network. Networking features of the metropolitan area network are as follows. There are a relatively small quantity of access points, and the quantity is generally not greater than eight, an access ring is relatively short, and is generally not longer than 20 km. According to the foregoing solution, not only a performance requirement is met, but also implementation is easy under a condition of same performance, and costs are relatively low.

[0113] When the access ring needs a higher bandwidth, an optical module may be added in an access point or a convergence point, to expand a bandwidth. For example, when a 100 G bandwidth is needed, two 50 GE optical modules may be used.

[0114] A person skilled in the art should understand that the embodiments of this application may be provided as a method, a system, or a computer program product. Therefore, this application may use a form of hardware only embodiments, software only embodiments, or embodiments with a combination of software and hardware. In addition, this application may use a form of a computer program product that is implemented on one or more computer-usable storage media (including but not limited to a disk memory, a compact disc-read only memory (CD-ROM), and an optical memory) that include computer usable program code.

[0115] This application is described with reference to the flowcharts and/or block diagrams of the method, the device (system), and the computer program product according to this application. It should be understood that computer program instructions may be used to implement each process and/or each block in the flowcharts and/or the block diagrams and a combination of a process and/or a block in the flowcharts and/or the block diagrams. These computer program instructions may be provided for a general-purpose computer, a special-purpose computer, an embedded processor, or a processor of another programmable data processing device to generate a machine such that the instructions executed by a computer or a processor of another programmable data processing device generate an apparatus for implementing a specific function in one or more processes in the flowcharts and/or in one or more blocks in the block diagrams.

[0116] These computer program instructions may be stored in a computer readable memory that can instruct the computer or another programmable data processing device to work in a specific manner such that the instructions stored in the computer readable memory generate an artifact that includes an instruction apparatus. The instruction apparatus implements a specific function in one or more processes in the flowcharts and/or in one or more blocks in the block diagrams.

[0117] These computer program instructions may be loaded onto a computer or another programmable data processing device such that a series of operations and steps are performed on the computer or the other programmable device, thereby generating computer-implemented processing. Therefore, the instructions executed on the computer or the other programmable device provides steps for implementing a specific function in one or more processes in the flowcharts and/or in one or more blocks in the block diagrams.

[0118] Obviously, a person skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. In this way, this application is intended to cover these modifications and variations of this application provided that they fall within the scope of protection defined by the following claims and their equivalent technologies.