CASCADE-FORM WAVELENGTH DIVISION MULTIPLEXING OPTOELECTRONIC TRANSCEIVER DEVICE, SYSTEM AND METHOD

Abstract

The invention relates to an optoelectronic transceiver device comprising a first optical connector (OC1) capable of connection to a first bidirectional optical fibre (OF1), and a second optical connector (OC2) capable of connection to a second bidirectional optical fibre (OF2), the device further comprising: an insertion-extraction module (ADM) capable of: extracting a wave-length (λ.sub.Rx) from a plurality of wavelengths constituting a first optical signal received by the first optical connector (OC1) and transmitting the first optical signal without the extracted wavelength to the second optical connector (OC2); inserting a wavelength (λ.sub.Tx) into a second optical signal received by the second optical connector (OC2) and transmitting the second optical signal with the inserted wavelength to the first optical connector (OC1); an electric-optical conversion module (EC1) capable of providing the insertion-extraction module with the wavelength (λ.sub.Tx) inserted into the second optical signal from an incoming electric signal (Data Tx); and an optical-electric conversion module (EC2) capable of converting the wavelength (λ.sub.Rx) extracted from the first optical signal by the insertion-extraction module into an outgoing electric signal (Data Rx).

Claims

1. An optoelectronic emitter-receiver device comprising a first optical connector (OC1) able to be connected to a first bidirectional optical fiber (OF1), and a second optical connector (OC2) able to be connected to a second bidirectional optical fiber (OF2), the device furthermore comprising: an insertion-extraction module (ADM) able to: extract a wavelength (λ.sub.Rx) in a plurality of wavelengths making up a first optical signal received by the first optical connector (OC1) and transmit the first optical signal without the extracted wavelength to the second optical connector (OC2); insert a wavelength (λ.sub.Tx) into a second optical signal received by the second optical connector (OC2) and transmit the second optical signal with the inserted wavelength to the first optical connector (OC1); an electrical-optical conversion module (EC1) able to provide the insertion-extraction module with the wavelength (λ.sub.Tx) inserted into the second optical signal on the basis of an incoming electrical signal (Data Tx); and an optical-electrical conversion module (EC2) able to convert the wavelength (λ.sub.Rx) extracted from the first optical signal by the insertion-extraction module into an outgoing electrical signal (Data Rx).

2. The optoelectronic emitter-receiver device as claimed in claim 1, furthermore comprising a selection module (WLS) for selecting the wavelengths to be inserted and extracted, configured to instruct the insertion-extraction module regarding the wavelength (λ.sub.Rx) to be extracted from the first optical signal and the wavelength (λ.sub.Tx) to be inserted into the second optical signal.

3. The optoelectronic emitter-receiver device as claimed in claim 1, comprising an electrical socket able to transmit the incoming and outgoing electrical signals, said socket being able to connect in a removable manner to an optical-line terminal port (P1, P2, P3).

4. The optoelectronic emitter-receiver device as claimed in claim 3, where the electrical socket is furthermore able to transmit to the selection module (WLS) an electrical signal comprising information ({λ.sub.Tx, λ.sub.Rx}) relating to the wavelengths to be inserted and extracted.

5. The optoelectronic emitter-receiver device as claimed in claim 3, where an electrical signal comprising information ({λ.sub.Tx, λ.sub.Rx}) relating to the wavelengths to be inserted and extracted is transmitted to the selection module (WLS) by an electrical socket distinct from the electrical socket able to transmit the incoming and outgoing electrical signals.

6. The optoelectronic emitter-receiver device as claimed in claim 1, where the optical connectors (OC1, OC2) are able to connect in a removable manner to the bidirectional optical fibers (OF1, OF2).

7. A system for connecting a plurality of ports (P1, P2, P3) of optical-line terminals to an optical distribution network, the optical-line-terminal ports being connected to an optoelectronic emitter-receiver device comprising a first optical connector (OC1) able to be connected to a first bidirectional optical fiber (OF1), and a second optical connector (OC2) able to be connected to a second bidirectional optical fiber (OF2), the device furthermore comprising: an insertion-extraction module (ADM) able to: extract a wavelength (λ.sub.Rx) in a plurality of wavelengths making up a first optical signal received by the first optical connector (OC1) and transmit the first optical signal without the extracted wavelength to the second optical connector (OC2); insert a wavelength (λ.sub.Tx) into a second optical signal received by the second optical connector (OC2) and transmit the second optical signal with the inserted wavelength to the first optical connector (OC1); an electrical-optical conversion module (EC1) able to provide the insertion-extraction module with the wavelength (λ.sub.Tx) inserted into the second optical signal on the basis of an incoming electrical signal (Data Tx); and an optical-electrical conversion module (EC2) able to convert the wavelength (λ.sub.Rx) extracted from the first optical signal by the insertion-extraction module into an outgoing electrical signal (Data Rx); the devices (XFP1, XFP2, XFP3) of the plurality being connected together while forming a cascade, the second optical connector (OC2) of a device of the cascade being linked by optical fiber to the first optical connector (OC1) of a following device in the cascade, the first optical connector of the first device (XFP1) of the cascade being linked to the optical distribution network by an optical fiber.

8. A method of optoelectronic emission-reception between a first optical connector (OC1) able to be connected to a first bidirectional optical fiber (OF1), and a second optical connector (OC2) able to be connected to a second bidirectional optical fiber (OF2), the method comprising the following steps: extraction (E2) of a wavelength (λ.sub.Rx) in a plurality of wavelengths making up a first optical signal received by the first optical connector (OC1); transmission (E3) of the first optical signal without the extracted wavelength to the second optical connector (OC2); insertion (E6) of a wavelength (λ.sub.Tx) into a second optical signal received by the second optical connector (OC2); transmission (E7) of the second optical signal with the inserted wavelength to the first optical connector (OC1); obtaining (E5) of the wavelength (λ.sub.Tx) inserted into the second optical signal by conversion of an incoming electrical signal (Data Tx); conversion (E4) of the wavelength (λ.sub.Rx) extracted from the first optical signal into an outgoing electrical signal (Data Rx).

9. The optoelectronic emitter-receiver device as claimed in claim 2, comprising an electrical socket able to transmit the incoming and outgoing electrical signals, said socket being able to connect in a removable manner to an optical-line terminal port (P1, P2, P3).

Description

4. PRESENTATION OF THE FIGURES

[0039] Other advantages and characteristics of the invention will be more clearly apparent on reading the following description of particular embodiments of the invention which are given by way of simple illustrative and nonlimiting example, and of the appended drawings, among which:

[0040] FIG. 1 presents a mixed optical distribution infrastructure, according to the prior art,

[0041] FIG. 2 presents a mixed optical distribution infrastructure, according to a particular embodiment of the invention,

[0042] FIG. 3 presents an optoelectronic emitter-receiver device according to a particular embodiment of the invention,

[0043] FIG. 4 presents an exemplary implementation of a cascade of optoelectronic emitter-receiver devices according to a particular embodiment of the invention,

[0044] FIG. 5 presents the method for receiving an optical signal implementing the receiver device according to a particular embodiment of the invention.

5. DETAILED DESCRIPTION OF AT LEAST ONE EMBODIMENT OF THE INVENTION

[0045] In the subsequent description, embodiments of the invention are presented in the case of mixed optical distribution infrastructures using WDM and/or TWDM techniques, in addition to TDM techniques. These infrastructures can comprise passive optical networks (PON) currently undergoing or shortly to undergo standardization at the ITU-T, such as the PON networks of NG-PON2 type, as well as other types of networks, in addition to or in place of PON networks, such as for example point-to-point optical networks.

[0046] FIG. 1 presents an ODN-AA mixed optical distribution infrastructure, according to the prior art.

[0047] For simplicity of illustration, this and the following figure show only a few TDM OLTs and only a few TWDM or WDM OLT ports, knowing that they may reach several tens or indeed several hundred in number in one and the same mixed optical distribution infrastructure. Likewise, only one ONU per OLT or per OLT port is illustrated, knowing that each OLT typically serves 64 or 128 ONUs.

[0048] In such an infrastructure mixing TDM, TWDM and WDM techniques, the OLTs of TDM type such as “GPON OLT” and “XGPON OLT” are connected by bidirectional interfaces respectively IF.sub.GPON and IF.sub.XGPON, on optical fiber, directly to a so-called “co-existence” CEx box. Other interfaces such as for example the interface IF.sub.Video of a video network front end can also be connected to the CEx box.

[0049] The ports P1, P2 and P3 of an OLT of TWDM type such as “TWDM OLT” are not connected directly to the CEx box but through a WM intermediate multiplexer/demultiplexer so that a single bidirectional interface IF.sub.TWDM, covering all the TWDM wavelength channels on a single optical fiber, is presented to the CEx box. This WM element must be specifically configured for the wavelengths that the operator envisages using with their TWDM OLT ports. The CEx box is itself connected by a bidirectional optical fiber to one or more couplers S, positioned in series at a distance relatively close to the users served by the mixed infrastructure. A single coupler is shown here for simplicity. The coupler S is connected to the optical line terminals of the users, denoted “GPON ONU”, “XGPON ONU”, “TWDM ONU”, “GPON+RF ONU”, etc.

[0050] It should be noted that OLTs of point-to-point type, not illustrated in FIG. 1, each use an upgoing and downgoing wavelength pair, and therefore have bidirectional signals which also need to be grouped together by a WM element, It is therefore understood that according to the prior art, several WM elements may thus have to be connected to a single CEx box.

[0051] FIG. 2 presents an ODN mixed optical distribution infrastructure, according to a particular embodiment of the invention.

[0052] In this particular embodiment of the invention, the ports P1, P2 and P3 of the OLT “TWDM OLT” are each equipped with an optoelectronic emitter-receiver device according to the invention, denoted respectively XFP1, XFP2 and XFP3. The particular feature of this device is to tap off, from a bidirectional optical signal, the upgoing wavelength associated with the port of the OLT, and to insert into this bidirectional optical signal the downgoing wavelength associated with the port of the OLT, while leaving the other wavelengths of the bidirectional optical signal intact. By virtue of this particular feature, the MW element is no longer necessary since it suffices to connect a single of the devices of OLT ports to the CEx box through a bidirectional optical fiber, and then to connect the other devices to this device in cascade, through bidirectional optical fibers.

[0053] It is understood that not only are one or more WM boxes no longer necessary but also that no modification is necessary in the other elements of the optical distribution infrastructure, such as the CEx box and the splitter, or in the ONUs on the clients' side.

[0054] It should be noted that the invention also applies to the OLTs of point-to-point type, not illustrated in FIG. 2.

[0055] FIG. 3 presents an optoelectronic emitter-receiver device according to a particular embodiment of the invention.

[0056] Such a device XFPx comprises the following elements or modules: [0057] an optical connector OC1 able to connect an optical fiber OF1 in a removable manner; [0058] an optical connector OC2 able to connect an optical fiber OF2 in a removable manner; the connectors OC1 and OC2 are for example of LC type, thereby making it possible for the optical fibers OF1 and OF2 to be connected and disconnected easily and independently; [0059] a wavelength insertion-extraction module ADM able to insert a wavelength λ.sub.Tx into a bidirectional optical signal carried by the optical fiber OF1, able to extract a wavelength λ.sub.Rx of the bidirectional optical signal carried by the optical fiber OF1, and able to allow the other wavelengths of the bidirectional optical signal carried by the optical fiber OF1 to pass through the optical fiber OF1 to an optical fiber OF2, and vice versa; such a module ADM is also known by the term “add-drop multiplexer”; [0060] a module WLS for selecting the wavelength to be inserted λ.sub.Tx and the wavelength to be extracted λ.sub.Rx, able to receive information {λ.sub.Tx, λ.sub.Rx} relating to these wavelengths and to transmit corresponding instructions to the module ADM; the selection module WLS can be included in the module ADM; [0061] a bidirectional optical multiplexing-demultiplexing module BMDM able to multiplex the wavelength λ.sub.Tx and to demultiplex the wavelength λ.sub.Rx in the/of the signal passing through the module ADM; [0062] a conversion module TE2O able to convert a downgoing electrical signal transporting data Tx into an optical signal of downgoing wavelength λ.sub.Tx; [0063] a conversion module RO2E able to convert an upgoing wavelength λ.sub.Rx into an upgoing electrical signal transporting data Rx; [0064] an electrical connector EC1 able to connect electrically and in a removable manner to an OLT port able to emit a downgoing electrical signal transporting data Tx, the connector EC1 being connected to the module TE2O; [0065] an electrical connector EC2 able to connect electrically and in a removable manner to an OLT port able to receive an upgoing electrical signal transporting data Rx, the connector EC2 being connected to the module RO2E; the electrical connectors EC1 and EC2 are for example combined into a single connector of the same type as the electrical connector of a module SFP+ or XFP, thereby making it possible to embed the entire device in a single optical module SFP+ or XFP, with a single electrical connector on the front face and two optical connectors, for example of LC type, on the front face.

[0066] FIG. 4 presents an exemplary implementation of a cascade of optoelectronic emitter-receiver devices according to a particular embodiment of the invention.

[0067] In this cascade, only the device XFP1 is connected to the CEx box by an interface IF.sub.TWDM and the optical fiber OF1. The bidirectional optical signal carried by the optical fiber OF1 comprises 3 downgoing wavelengths: λ.sub.T1, λ.sub.T2, λ.sub.T3, and 3 upgoing wavelengths: λR.sub.1, λ.sub.R2, λ.sub.R3.

[0068] The device XFP1 receives an electrical signal “Tx:λ.sub.T1” from the port P1 of the TWDM OLT, which it converts into an optical signal of wavelength λ.sub.T1 which it inserts into the bidirectional optical signal carried by the optical fiber OF1.

[0069] The device XFP1 extracts a signal of wavelength λ.sub.R1 from the bidirectional optical signal carried by the optical fiber OF1 and converts it into an electrical signal “Rx:λ.sub.R1” which it emits to the port P1 of the TWDM OLT.

[0070] A bidirectional optical signal identical to that carried by the optical fiber OF1, but devoid of the wavelengths λ.sub.T1 and λ.sub.R1, passes through the device XFP1 and is carried by the optical fiber OF2.

[0071] The bidirectional optical signal carried by the optical fiber OF2 therefore comprises 2 downgoing wavelengths: λ.sub.T2, λ.sub.T3, and 2 upgoing wavelengths: λ.sub.R2, λ.sub.R3.

[0072] The device XFP2 receives an electrical signal “Tx:λ.sub.T2” from the port P2 of the TWDM OLT, which it converts into an optical signal of wavelength λ.sub.T2 which it inserts into the bidirectional optical signal carried by the optical fiber OF2.

[0073] The device XFP2 extracts a signal of wavelength λ.sub.R2 from the bidirectional optical signal carried by the optical fiber OF2 and converts it into an electrical signal “Rx:λ.sub.R2” which it emits toward the port P2 of the TWDM OLT.

[0074] A bidirectional optical signal identical to that carried by the optical fiber OF2, but devoid of the wavelengths λ.sub.T2 and λ.sub.R2, passes through the device XFP2 and is carried by the optical fiber OF3.

[0075] The bidirectional optical signal carried by the optical fiber OF3 therefore comprises 1 downgoing wavelength: λ.sub.T3, and 1 upgoing wavelength: λ.sub.R3.

[0076] The device XFP3 receives an electrical signal “Tx:λ.sub.T3” from the port P3 of the TWDM OLT, which it converts into an optical signal of wavelength λ.sub.T3 which it inserts into the bidirectional optical signal carried by the optical fiber OF3.

[0077] The device XFP3 extracts a signal of wavelength λ.sub.R3 from the bidirectional optical signal carried by the optical fiber OF3 and converts it into an electrical signal “Rx:λ.sub.R3” which it emits toward the port P3 of the TWDM OLT.

[0078] FIG. 5 presents the method for receiving an optical signal implementing the receiver device according to a particular embodiment of the invention.

[0079] During a step E1, the wavelengths λ.sub.Tx and λ.sub.Rx are selected. They are specific to the OLT equipped with the device implementing the method, and correspond respectively to the downgoing and upgoing direction of the transmission of the data in the mixed optical distribution infrastructure, For convenience they are called downgoing and upgoing wavelength respectively,

[0080] During a step E2, the upgoing wavelength λ.sub.Rx is extracted from a first optical signal received on a first optical connector.

[0081] During a step E3, the first optical signal is transmuted to a second optical connector, without the upgoing wavelength λ.sub.Rx.

[0082] During a step E4, that may be simultaneous with step E6, the upgoing wavelength λ.sub.Rx is converted into an upgoing electrical signal transporting data Rx.

[0083] During a step E5, a so-called downgoing electrical signal, transporting data Tx intended to be transmitted in the downgoing direction of transmission, is converted into a downgoing wavelength λ.sub.Tx.

[0084] During a step E6, the downgoing wavelength λ.sub.Tx is inserted into a second optical signal received on the second optical connector.

[0085] During a step E7, the second optical signal is transmitted to the first optical connector, with the downgoing wavelength λ.sub.Tx.

[0086] The string of steps E2, E3 and E4 can be simultaneous with the string of steps E5, E6, E7.

[0087] An optical fiber connected to the first connector is indeed bidirectional, since it transports both the downgoing wavelength λ.sub.Tx transmitted during step E6, and the upgoing wavelength λ.sub.Rx received during step E2.

[0088] Likewise, as is apparent for the devices XFP1 and XFP2 of FIG. 4, when the optical fiber connected to the second connector is connected by its other end to the first connector of another device, this optical fiber is also bidirectional.

[0089] The exemplary embodiments of the invention which have just been presented are merely a few of the conceivable embodiments. They show that the invention makes it possible to simplify an optical distribution infrastructure mixing TDM and WDM or TWDM, by equipping each WDM or TWDM OLT port with a plug-in and removable optoelectronic emitter-receiver device having the particular feature of inserting and tapping off the upgoing and downgoing wavelengths associated with the port, and then by cascading the devices with one another. Thus, the optical signal carried by the optical fiber connected to the first of the cascade covers the whole WDM or TWDM wavelength spectrum, and this optical fiber can be connected directly to the mixed optical distribution infrastructure, without the intermediary of a wavelength multiplexer-demultiplexer as in the prior art.