Example fiber amplifiers and gain adjustment methods for the fiber amplifiers are described. One example fiber amplifier includes a first power amplifier, a wavelength level adjuster, and a controller, where the first power amplifier is connected to the wavelength level adjuster. The controller includes a first input end and a control output end. The first input end is configured to receive an input optical signal, and the control output end is configured to output a first amplification control signal to the first power amplifier, and output an adjustment control signal to the wavelength level adjuster. The wavelength level adjuster is configured to perform power adjustment on each wavelength in a separate manner based on the adjustment control signal.

This application discloses an optical amplifier including a Raman fiber amplifier (RFA), a dynamic gain equalizer (DGE), a filter, an erbium-doped fiber amplifier (EDFA), an RFA gain controller, an EDFA gain controller, and an optical amplifier controller. The optical amplifier controller is configured to provide instructions to and receive feedback from the RFA and EDFA gain controllers. The RFA and the EDFA are configured to amplify an optical signal. The RFA gain controller is configured to control the RFA to adjust a gain. The EDFA gain controller is configured to control the EDFA to adjust a gain. The DGE adjusts insertion loss. The filter is configured to filter an amplified spontaneous emission signal produced in an optical amplification process of the RFA.

An excitation light source apparatus capable of assuring an excellent optical transmission characteristic even at occurrence of a gain tilt is provided. The excitation light source apparatus comprises an excitation light outputting means, a control signal detection means, a control signal detection means, an excitation light control means, and a multiplexing means. The excitation light outputting means outputs excitation light for Raman amplification. The control signal detection means detects a control signal of the excitation light outputting means from beams of WDM signal light transmitted through optical fibers in an upstream direction and a downstream direction. The excitation light control means controls the excitation light outputting means, based on the control signal. The multiplexing means multiplexes the excitation light and each of the beams of the WDM signal light, and outputs the respective multiplexed beams of light to the optical fiber.

A low-noise amplifier includes a gain medium and two or more amplifier stages. Each amplifier stage includes an optical filter to pass all wavelengths of a respective input optical signal in a given propagation direction over the gain medium and reflect wavelengths above a respective threshold wavelength received in the opposite direction, and a respective Raman pump to inject a pump light centered at a wavelength lower than the threshold wavelength onto the gain medium for transmission in the given direction. A first amplifier stage outputs a first combined optical signal including all wavelengths of the respective input optical signal and a pump light injected by the respective Raman pump. The second amplifier stage receives the first combined optical signal as its input and outputs a second combined optical signal including all wavelengths of the first combined optical signal and a pump light injected by the respective Raman pump.

Examples described herein relate to a receiver training method. To configure a static gain for at least one static gain amplifier and a target amplitude for a dynamic gain amplifier, a dynamic gain adjustment is disabled and the dynamic gain amplifier is configured to apply a predetermined fixed gain to the static gain amplified signal to generate a test signal. Furthermore, an effective static gain magnitude for at least one static gain amplifier and an effective amplitude for the test signal are determined based on a link performance metric. The static gain is set to the effective static gain magnitude, and a target amplitude for the dynamic gain amplifier is set to the effective amplitude. Then, the dynamic gain adjustment may be enabled to maintain an amplitude of a dynamic gain amplified signal at an output of the dynamic gain amplifier at the target amplitude by varying the dynamic gain.

An apparatus for automatic amplifier gain setting of an optical amplifier, said apparatus comprising an optical channel counter, OCC, unit configured to detect a number of channels present in an optical transmission spectrum; a determination unit configured to determine an average power per channel calculated by dividing a measured total power of a signal input and/or signal output of the optical amplifier by the number of channels detected by said optical channel counter, OCC, unit and a gain adjustment unit configured to adjust the amplifier gain of said optical amplifier automatically depending on a calculated power difference between a predetermined desired power per channel and the determined average power per channel provided by said determination unit.

Example fiber amplifiers and gain adjustment methods for the fiber amplifiers are described. One example fiber amplifier includes a first power amplifier, a wavelength level adjuster, and a controller, where the first power amplifier and the wavelength level adjuster are sequentially connected. The controller includes a first input end and a control output end. The first input end is configured to receive an input optical signal of the fiber amplifier, and the control output end is configured to output a first amplification control signal to the first power amplifier, and output an adjustment control signal to the wavelength level adjuster. The wavelength level adjuster is configured to perform power adjustment on each wavelength based on the adjustment control signal.

A submarine optical communication system control device (1) according to the present invention includes: a light intensity distribution determination device (2) configured to determine an optimum distribution of signal light intensity of each optical path for each allocated frequency; a light intensity distribution measuring device (3) configured to measure a light intensity distribution of an optical path after transmission through a submarine cable transmission line; an equalization setting calculation unit (4) configured to calculate a gain equalization setting for compensating for the difference between an optimum distribution in the light intensity distribution determination device and a measured distribution in the light intensity distribution measuring device; and a variable gain equalizer (5) configured to compensate for a light intensity distribution of an optical path to the optimum distribution, based on a gain equalization setting in the equalization setting calculation unit.

The present invention relates to the technical field of optical communications, and relates to an optical amplification method and an amplifier, and in particular, to a self-adaptive wave band amplification method and an amplifier. The present invention consists of a master amplifying unit and a slave amplifying unit, and can autonomously detect the service signal wave band range of an optical transmission line, and according to the detection result, the two amplifying units do not need to perform scheduling or configuration from the level of network management, and perform direct interaction and action from the bottom layer to implement self-adaptive on, off and adjustment in real time. On one hand, power consumption is reduced, and energy is saved; and on the other hand, the performance is optimized, and an optimal optical amplification index is obtained.

A submarine optical communication system control device (1) according to the present invention includes: a light intensity distribution determination device (2) configured to determine an optimum distribution of signal light intensity of each optical path for each allocated frequency; a light intensity distribution measuring device (3) configured to measure a light intensity distribution of an optical path after transmission through a submarine cable transmission line; an equalization setting calculation unit (4) configured to calculate a gain equalization setting for compensating for the difference between an optimum distribution in the light intensity distribution determination device and a measured distribution in the light intensity distribution measuring device; and a variable gain equalizer (5) configured to compensate for a light intensity distribution of an optical path to the optimum distribution, based on a gain equalization setting in the equalization setting calculation unit.