A method of interrogating a WDM optical communication system is provided to obtain one or more performance parameters. In accordance with the method, an optical probe wavelength is generated and possibly modulated in a prescribed manner. The probe signal is transmitted along a selected optical path through the WDM optical communication system for a duration of time that is less than a response time of network elements that impact signal quality along the selected optical path.

Systems and methods include causing perturbations across optical spectrum; probing responses across some or all of the optical spectrum after the perturbations; and determining a nonlinear transfer function based on the responses. The nonlinear transfer function can include a representation of any of end-to-end channel powers, Signal-to-Noise Ratio (SNR), Noise-to-Signal Ratio (NSR), Bit Error Rate (BER), Q, and Mean Squared Error (MSE).

Disclosed are an optical signal communication method, and an optical signal transmission device and an optical signal reception device which perform the method. The optical signal communication method may comprise the steps of: receiving input data to be modulated into an optical signal, modulating the input data into the optical signal, and transmitting the optical signal to an optical signal reception device, wherein the optical signal includes a start pulse and an end pulse, and a time interval between the start pulse and the end pulse is determined on the basis of a data value of the input data.

Disclosed are an optical signal communication method, and an optical signal transmission device and an optical signal reception device which perform the method. The optical signal communication method may comprise the steps of: receiving input data to be modulated into an optical signal, modulating the input data into the optical signal, and transmitting the optical signal to an optical signal reception device, wherein the optical signal includes a start pulse and an end pulse, and a time interval between the start pulse and the end pulse is determined on the basis of a data value of the input data.

A method to determine the types of optical fibers forming a link of an optical communication network. By scanning a signal's bit error rate at a receiver end, as a function of a pre-dispersion applied to a signal at a transmitter end, local minimums in the curve indicate the presence of amplifiers, and therefore fiber span extremities. By determining the accumulated dispersion at each fiber extremity, a ratio of dispersion per span length can be obtained and the span's coefficient of chromatic dispersion be inferred, thereby identifying the type of fiber. Alternatively, a signal's signal-to-noise ratio can be scanned, instead of its bit error rate. In a typical network, the required instrumentation is pre-existing.

In one embodiment, a method includes receiving at a remote network device, power and data from a central network device, wherein the power is used to power the remote network device, performing auto-negotiation with the central network device, wherein the auto-negotiation includes operating the remote network device in a low voltage mode during fault sensing of a power circuit at the remote network device, and selecting a power operating mode, wherein selecting the power operating mode includes selecting a high voltage mode if no fault is detected during the fault sensing, the high voltage mode comprising DC (direct current) pulse power. An apparatus is also disclosed herein.

A domain A (10) including one or more boundary nodes (13) is provided with a VIF (13v) which is a virtual connection unit for virtual connection with an adjacent domain B (20), and the domain B (20) including one or more boundary nodes (21) is provided with a VIF (21v) which is a virtual connection unit for virtual connection with the domain A (10), in which the boundary node (13) notifies the VIF (21v) adjacent to the VIF (13v) of a VIF warning by receiving an internal warning in a format capable of being processed within the domain A (10), and converting the internal warning into the VIF warning which is a warning of the VIF (13v) capable of being processed in common between the domains, and the boundary node (21) transfers the internal warning to another node within the domain B (20) by converting the VIF warning of the VIF (21v) into an internal warning in a format capable of being processed within the domain B (20).

A domain A (10) including one or more boundary nodes (13) is provided with a VIF (13v) which is a virtual connection unit for virtual connection with an adjacent domain B (20), and the domain B (20) including one or more boundary nodes (21) is provided with a VIF (21v) which is a virtual connection unit for virtual connection with the domain A (10), in which the boundary node (13) notifies the VIF (21v) adjacent to the VIF (13v) of a VIF warning by receiving an internal warning in a format capable of being processed within the domain A (10), and converting the internal warning into the VIF warning which is a warning of the VIF (13v) capable of being processed in common between the domains, and the boundary node (21) transfers the internal warning to another node within the domain B (20) by converting the VIF warning of the VIF (21v) into an internal warning in a format capable of being processed within the domain B (20).

An extinction ratio testing system (10) includes a microcontroller (102), an extinction ratio tester (104), and a thermostat (106). The microcontroller (102) controls the thermostat (106) to maintain an optical transceiver module (20) at a predetermined high temperature, and then the microcontroller (102) controls the extinction ratio tester (104) to test an extinction ratio of the optical transceiver module (20). If the extinction ratio is lower than a standard extinction ratio, the microcontroller (102) controls the optical transceiver module (20) to increase a laser operating current (212) of the optical transceiver module (20) to increase the extinction ratio.

An optical power value transmission method and system, and a related device is disclosed. The method includes: A source network device obtains optical multiplexing section link information that indicates an optical fiber connection relationship between any two adjacent network devices between the source and a target network device of an optical multiplexing section which are located in different data communication networks. The source network device determines, based on the optical multiplexing section link information, a first output port that connected to a downstream network device by using a first optical fiber, and the downstream network device is connected to the source network device and that is indicated by the optical multiplexing section link information. The source network device obtains, on the first output port, a first output power value of an optical signal and sent it to the downstream network device by using the first optical fiber.