The embodiments of the present disclosure provide an avalanche photo diode (APD) performance detection method and apparatus for an optical module, and an optical network and a medium. The method is applicable to an optical network including an optical module and an optical network unit (ONU); the method includes: selecting at least one optical network unit identifier (ONU ID) as a detection ONU ID; allocating a bandwidth to the detection ONU ID and enabling the bandwidth; acquiring received optical power of the optical module for the detection ONU ID; and determining, on the basis of the received optical power, whether the performance of an APD in the optical module deteriorates.

The present invention is to provide a backscattered light amplification device, an optical pulse test apparatus, a backscattered light amplification method, and an optical pulse test method for amplifying a desired propagation mode of Rayleigh backscattered light with a desired gain by stimulated Raman scattering in a fiber under test having the plurality of propagation modes. The backscattered light amplification device according to the present invention is configured to control individually power, incident timing, and pulse width of a pump pulse for each propagation mode when the pump pulse is incident in a plurality of propagation modes after the probe pulse is input to the fiber under test in any propagation mode.

A first optical transceiver includes a transmission signal processor that generates a multi-valued pulse amplitude modulation signal including a fixed bit pattern. The first optical transceiver includes an optical transmitter that transmits the multi-valued pulse amplitude modulation signal as an optical transmission signal. The first optical transceiver includes an optical receiver that receives an optical adjustment signal from a second optical transceiver to reproduce an adjustment signal from the optical adjustment signal. The first optical transceiver includes a first controller that controls the transmission signal processor based on a bit error rate included in the optical adjustment signal to adjust light power at each level of the optical transmission signal.

A first optical transceiver includes a transmission signal processor that generates a multi-valued pulse amplitude modulation signal including a fixed bit pattern. The first optical transceiver includes an optical transmitter that transmits the multi-valued pulse amplitude modulation signal as an optical transmission signal. The first optical transceiver includes an optical receiver that receives an optical adjustment signal from a second optical transceiver to reproduce an adjustment signal from the optical adjustment signal. The first optical transceiver includes a first controller that controls the transmission signal processor based on a bit error rate included in the optical adjustment signal to adjust light power at each level of the optical transmission signal.

An excitation light source apparatus includes: an excitation light source to generate Raman excitation light in a drive state and to stop generating the Raman excitation light in a stop state; a light source controller to control the intensity of the Raman excitation light in the drive state; a light level measuring instrument to measure the light level of signal light; a logarithmic converter to convert at least one measurement result of measuring by the light level measuring instrument to a logarithmic value; and a main controller to decide a correction value based on the logarithmic value of the at least one measurement result in the stop state. The main controller controls the light source controller by using the correction value and a preset gain control target value.

An excitation light source apparatus includes: an excitation light source to generate Raman excitation light in a drive state and to stop generating the Raman excitation light in a stop state; a light source controller to control the intensity of the Raman excitation light in the drive state; a light level measuring instrument to measure the light level of signal light; a logarithmic converter to convert at least one measurement result of measuring by the light level measuring instrument to a logarithmic value; and a main controller to decide a correction value based on the logarithmic value of the at least one measurement result in the stop state. The main controller controls the light source controller by using the correction value and a preset gain control target value.

Embodiments of an optical amplification apparatus are disclosed which include a first optical amplifier, a second optical amplifier, and a mode exchanger. The first optical amplifier is connected to an input port of the mode exchanger, and the second optical amplifier is connected to an output port of the mode exchanger. The first optical amplifier is configured to amplify optical signals carried in a plurality of transmission modes of a few-mode fiber, the plurality of transmission modes of the few-mode fiber may be grouped into N groups, each group includes two transmission modes, and N is a positive integer greater than or equal to 1. The mode exchanger is configured to exchange the two transmission modes carrying optical signals in each group. The second optical amplifier is configured to amplify the optical signals that are carried in the two transmission modes in each group and whose modes are exchanged.

Embodiments of an optical amplification apparatus are disclosed which include a first optical amplifier, a second optical amplifier, and a mode exchanger. The first optical amplifier is connected to an input port of the mode exchanger, and the second optical amplifier is connected to an output port of the mode exchanger. The first optical amplifier is configured to amplify optical signals carried in a plurality of transmission modes of a few-mode fiber, the plurality of transmission modes of the few-mode fiber may be grouped into N groups, each group includes two transmission modes, and N is a positive integer greater than or equal to 1. The mode exchanger is configured to exchange the two transmission modes carrying optical signals in each group. The second optical amplifier is configured to amplify the optical signals that are carried in the two transmission modes in each group and whose modes are exchanged.

A method for determining an optical signal power change, wherein the method includes: A first optical signal that includes a plurality of wavelength signals is obtained, where the plurality of wavelength signals are distributed in a plurality of bands. Then, an optical power of each band and a center wavelength signal of each band are detected, and a preset single-wavelength transmit power and a preset coefficient are obtained. Next, an equivalent quantity N of equivalent wavelength signals is determined, and an equivalent wavelength signal corresponding to the first optical signal is determined. Further, a target power that is used to compensate for a first power change value of the first optical signal in transmission over an optical fiber is determined based on the preset coefficient, the equivalent wavelength signal, the equivalent quantity, and the preset single-wavelength transmit power.

A method for determining an optical signal power change, wherein the method includes: A first optical signal that includes a plurality of wavelength signals is obtained, where the plurality of wavelength signals are distributed in a plurality of bands. Then, an optical power of each band and a center wavelength signal of each band are detected, and a preset single-wavelength transmit power and a preset coefficient are obtained. Next, an equivalent quantity N of equivalent wavelength signals is determined, and an equivalent wavelength signal corresponding to the first optical signal is determined. Further, a target power that is used to compensate for a first power change value of the first optical signal in transmission over an optical fiber is determined based on the preset coefficient, the equivalent wavelength signal, the equivalent quantity, and the preset single-wavelength transmit power.