A reconfigurable optical add/drop multiplexer (ROADM) includes a plurality of interconnected ROADM blocks. Each ROADM block includes an ingress switchable-gain amplifier, an output power detector coupled to an output of the ingress switchable gain amplifier, and a wavelength-selective switch coupled to the output of the ingress switchable gain amplifier. Each ROADM block includes a plurality of add/drop blocks coupled to the wavelength-selective switches of the plurality of ROADM blocks. The ROADM includes a controller configured to receive an indication of an output signal power from the output power detector and adjust gain and equalization parameters of the ingress switchable-gain amplifier based on the received indication of the output signal power.

A signal quality measurement device includes: a setting processing unit that sets respective passbands of WSSs; and a calculating unit that calculates quality of an optical signal by acquiring a first power of an optical component in a first wavelength band, and a second power of an optical component in a second wavelength band adjacent to the first wavelength band. When the setting processing unit sets each of the passbands of the WWSs, the calculating unit detects a combined power of various ASEs of the optical amplifiers from the second power, and detects the power of the optical signal from the first power and the second power. When the setting processing unit sets the passband of one of the WSSs, the calculating unit detects, from the second power, the ASE of an optical amplifier existing between one of the wavelength selective switches and the receiver.

Methods and systems for implementing a route and collect ROADM include a route stage incorporating a 1?2 wavelength selective element to split pass through wavelengths and dropped wavelengths from and input WDM signal. Additional optical functionality of the route and collect ROADM may be implemented using passive optical elements, such as a collect stage comprising an optical coupler to combine add wavelengths with the pass through wavelengths.

An optical node may include D (D?2) input ports, D output ports, and D degrees. Each degree may include an inbound M?N (M?D, N?2D) WSS and an outbound M?N WSS. Each inbound M?N WSS may include an input connected to one of the D input ports; inputs connected to outputs of inbound M?N WSSs of the other degrees; outputs connected to inputs of outbound M?N WSSs of the other degrees; outputs connected to inputs of inbound M?N WSSs of the other degrees; and a local drop port. Each outbound M?N WSS may include an output connected to one of the D input ports; outputs connected to inputs of outbound M?N WSSs of the other degrees; inputs connected to outputs of inbound M?N WSSs of the other degrees; inputs connected to outputs of outbound M?N WSSs of the other degrees; and a local add port.

Method and apparatus of an optical routing system (ORS) capable of automatically discovering intra-nodal fiber connections using a test channel transceiver (TCT) are disclosed. ORS, in one embodiment, includes a set of reconfigurable optical add-drop multiplexer (ROADM) modules, intra-nodal fiber connections, add-drop modules, and a test module. The ROADM modules are able to transmit or receive optical signals via optical fibers. The intra-nodal fiber connections are configured to provide optical connections. The add-drop modules are able to selectively make connections between input ports and output ports. The test module containing TCT is configured to identify at least a portion of intra-nodal connections of the ROADM via a test signal operating with a unique optical frequency.

A signal quality measurement device includes: a setting processing unit that sets respective passbands of WSSs; and a calculating unit that calculates quality of an optical signal by acquiring a first power of an optical component in a first wavelength band, and a second power of an optical component in a second wavelength band adjacent to the first wavelength band. When the setting processing unit sets each of the passbands of the WWSs, the calculating unit detects a combined power of various ASEs of the optical amplifiers from the second power, and detects the power of the optical signal from the first power and the second power. When the setting processing unit sets the passband of one of the WSSs, the calculating unit detects, from the second power, the ASE of an optical amplifier existing between one of the wavelength selective switches and the receiver.

A reconfigurable optical add/drop multiplexer (ROADM) includes a plurality of interconnected ROADM blocks. Each ROADM block includes an ingress switchable-gain amplifier, an output power detector coupled to an output of the ingress switchable gain amplifier, and a wavelength-selective switch coupled to the output of the ingress switchable gain amplifier. Each ROADM block includes a plurality of add/drop blocks coupled to the wavelength-selective switches of the plurality of ROADM blocks. The ROADM includes a controller configured to receive an indication of an output signal power from the output power detector and adjust gain and equalization parameters of the ingress switchable-gain amplifier based on the received indication of the output signal power.

An optical node may include D (D?2) input ports, D output ports, and D degrees. Each degree may include an inbound M?N (M?D, N?2D) WSS and an outbound M?N WSS. Each inbound M?N WSS may include an input connected to one of the D input ports; inputs connected to outputs of inbound M?N WSSs of the other degrees; outputs connected to inputs of outbound M?N WSSs of the other degrees; outputs connected to inputs of inbound M?N WSSs of the other degrees; and a local drop port. Each outbound M?N WSS may include an output connected to one of the D input ports; outputs connected to inputs of outbound M?N WSSs of the other degrees; inputs connected to outputs of inbound M?N WSSs of the other degrees; inputs connected to outputs of outbound M?N WSSs of the other degrees; and a local add port.

Method and apparatus of an optical routing system (ORS) capable of automatically discovering intra-nodal fiber connections using a test channel transceiver (TCT) are disclosed. ORS, in one embodiment, includes a set of reconfigurable optical add-drop multiplexer (ROADM) modules, intra-nodal fiber connections, add-drop modules, and a test module. The ROADM modules are able to transmit or receive optical signals via optical fibers. The intra-nodal fiber connections are configured to provide optical connections. The add-drop modules are able to selectively make connections between input ports and output ports. The test module containing TCT is configured to identify at least a portion of intra-nodal connections of the ROADM via a test signal operating with a unique optical frequency.

Methods and systems enable optimized placement of wavelength shifters in optical networks. The wavelength shifters may include O-E-O regenerators for a single wavelength and all optical wavelength shifters for one or more wavelengths. An auxiliary graph is used to represent various links in a provisioned optical path. By applying cost values to each of the links, different types of optimizations for network resource utilization may be realized.