System and method for improving performance in an optical link. The optical link includes a plurality of communication channels for transmitting an optical signal. The method is performed by a link controller of the optical link. The method comprises determining a noise level of at least one channel of the plurality of channels, determining a launch power offset for the at least one channel and performing link commissioning based at least in part on the launch power offset.

System and method for improving performance in an optical link. The optical link includes a plurality of communication channels for transmitting an optical signal. The method is performed by a link controller of the optical link. The method comprises determining a noise level of at least one channel of the plurality of channels, determining a launch power offset for the at least one channel and performing link commissioning based at least in part on the launch power offset.

Provided is an optical amplifier, an optical relay and an optical communication system that can amplify signal light of a plurality of systems and that can realize a reduction in costs. This optical amplifier amplifies and outputs signal light of a plurality of systems, the amplifier including: a plurality of impurity-doped optical fiber amplification units; a plurality of excitation light sources; a plurality of excitation light demultiplexing units; a plurality of excitation light multiplexing/demultiplexing units; and a plurality of multiplexing units. The plurality of excitation light sources include at least a first excitation light source and a second excitation light source that are driven commonly by a first driving current, and a third excitation light source that is driven by a second driving current of a different system than the first driving current.

Provided is an optical amplifier, an optical relay and an optical communication system that can amplify signal light of a plurality of systems and that can realize a reduction in costs. This optical amplifier amplifies and outputs signal light of a plurality of systems, the amplifier including: a plurality of impurity-doped optical fiber amplification units; a plurality of excitation light sources; a plurality of excitation light demultiplexing units; a plurality of excitation light multiplexing/demultiplexing units; and a plurality of multiplexing units. The plurality of excitation light sources include at least a first excitation light source and a second excitation light source that are driven commonly by a first driving current, and a third excitation light source that is driven by a second driving current of a different system than the first driving current.

An optical amplifier includes an input port for receiving an input optical signal;a wavelength division multiplexer (204) having a first input coupled to the input port, a second input coupled to a pump source (206), and an output coupled to an amplification fiber (208); and an integrated component (210) configured to provide output monitoring and isolation, wherein the integrated component (210) is configured to separate a first portion of a light signal received from the amplification fiber (208), direct the first portion to a photo detector, direct a second portion of the input light from the amplification fiber (208) to an output port, and attenuate light signals received from the output port.

Provided are a control method and system for a cascade hybrid amplifier, in which respective hybrid amplifiers in the cascade hybrid amplifier simultaneously start to implement a pump-starting process comprising: when the hybrid amplifier receives a request to start pumping, determining whether conditions are satisfied, if yes, determining stability of power of an input light of a Raman, starting pumping of an EDFA so that the EDFA enters into an APC operation mode; starting pumping of the Raman, and calculating a gain deviation according to the calculated input light powers before and after pump-starting of the Raman when no reflection alarm exists; and adjusting gain of the Raman according to the gain deviation, and switching to an AGC (automatic gain control) operation mode after the adjustment; and switching the EDFA to the AGC operation mode.

An amplifier receives an optical signal including a number of labeled channels via a fiber. The amplifier determines a count of the labeled channels and a spectral distribution of the labeled channels. The amplifier adjusts a parameter of the amplifier based on the count of the labeled channels and the spectral distribution of the labeled channels. The amplifier amplifies the optical signal at an adjusted output gain resulting from adjusting the parameter of the amplifier.

Disclosed are devices, systems, apparatuses, methods, products, and other implementations of GNSS repeater systems and methods for improving phase and frequency alignment of RF signals transported through fiber optic communication channels. Acquired RF signals are processed at a remote outdoor unit, where they are digitized, formatted into a CPRI frame, and timestamped. The timestamped CPRI frame is then transported over a fiber optic communication channel to an indoor head end unit. The indoor head end unit extracts timestamp and digitized RF signal from the CPRI frame. The timestamp is then used to synchronize a base transceiver station (BTS) and a precision time protocol (PTP) grand master with the remote outdoor unit.

Disclosed are devices, systems, apparatuses, methods, products, and other implementations of GNSS repeater systems and methods for improving phase and frequency alignment of RF signals transported through fiber optic communication channels. Acquired RF signals are processed at a remote outdoor unit, where they are digitized, formatted into a CPRI frame, and timestamped. The timestamped CPRI frame is then transported over a fiber optic communication channel to an indoor head end unit. The indoor head end unit extracts timestamp and digitized RF signal from the CPRI frame. The timestamp is then used to synchronize a base transceiver station (BTS) and a precision time protocol (PTP) grand master with the remote outdoor unit.

The light multiplexing/demultiplexing device comprises: a first demultiplexer that demultiplexes an inputted first wavelength-multiplexed signal light into a first signal light of a first wavelength band and a second signal light of a second wavelength band and outputs the first and the second signal light; a first amplifier that amplifies the second signal light from the first demultiplexer; a light processor that, based on the inputted second signal light and an inputted third signal light of the second wavelength band, outputs a fourth signal light; and a first multiplexer that multiplexes the fourth signal light with the first signal light from the first demultiplexer, further, the gain of the first amplifier is set such that the difference between power of the first signal light outputted from the first multiplexer and power of the fourth signal light outputted from the first multiplexer is equal to or less than a predetermined value.