In order to measure the signal quality of each of optical signals transmitted/received via a plurality of transmission lines, an optical communication system 1 is provided with a dummy light source 10 for outputting dummy light, a switching means 20 for outputting the dummy light to a first transmission line 40a, and a light-receiving means 30 for acquiring first signal quality from the dummy light received via the first transmission line 40a, the switching means 20 switching the output destination of the dummy light from the first transmission line 40a to a second transmission line 40b, and the light-receiving means 30 acquiring second signal quality from the dummy light received via the second transmission line 40b.

A light amplification device according to an example aspect of the invention includes a wavelength demultiplexing unit configured to demultiplex the wavelength division multiplexed signal light into a plurality of wavelength bands; a plurality of light amplification media configured to amplify the plurality of pieces of demultiplexed multiplex signal light; a wavelength multiplexing unit configured to multiplex the amplified demultiplexed multiplex signal light; a plurality of excitation energy supply units configured to supply excitation energy to each of the plurality of light amplification media; and a control unit, wherein the control unit includes a wavelength multiplexing/demultiplexing control unit configured to control the wavelength demultiplexing unit and the wavelength multiplexing unit in such a way that a starting wavelength and a wavelength number become an optimum starting wavelength and an optimum wavelength number when a sum of power consumption of the plurality of excitation energy supply units is minimized.

The present disclosure provides a data transceiving method, a data transceiving device, a wavelength configuration method and a wavelength configuration device. The data transceiving method includes that a first optical module receives control information sent by a second optical module; the first optical module adjusts transmission and receiving wavelengths according to the control information; and the first optical module executes transmission and receiving of data with the second optical module according to the adjusted transmission and receiving wavelengths.

Processing a received optical signal in an optical communication network includes equalizing a received optical signal to provide an equalized signal, demodulating the equalized signal according to an m-ary modulation format to provide a demodulated signal, decoding the demodulated signal according to an inner code to provide an inner-decoded signal, and decoding the inner-decoded signal according to an outer code. Other aspects include other features such as equalizing an optical channel including storing channel characteristics for the optical channel associated with a client, loading the stored channel characteristics during a waiting period between bursts on the channel, and equalizing a received burst from the client using the loaded channel characteristics.

An amplified hollow-core fiber (HCF) optical transmission system for low latency communications. The optical transmission system comprises a low-latency amplified HCF cable. The low-latency amplified HCF cable comprises multiple HCF segments (or HCF spans). Between consecutive HCF segments, the system comprises low-latency remote optically pumped amplifiers (ROPAs). Each ROPA comprises a gain fiber, a wavelength division multiplexing (WDM) coupler, and an optical isolator. Preferably, the ROPAs are integrated into the HCF cable. Each ROPA is pumped by a remote optical pump source, which provides pump light to the gain fiber. The gain fiber receives an optical transmission signal from the HCF. The WDM coupler combines the pump light with the optical transmission signal, thereby allowing the gain fiber to amplify the optical transmission signal to an amplified transmission signal. The amplified signal is transmitted to another HCF segment through the optical isolator.

Disclosed are techniques and amplifier stages that include wave division multiplexers, semiconductor optical amplifiers and wave division demultiplexers that amplify optical signals. An input optical signal having a first bandwidth is partitioned into a plurality of subband optical signals by thin film filters tuned to a selected bandwidth that is less than the first bandwidth. Each of the plurality of subband optical signals has a bandwidth that is a portion of the first bandwidth. Each subband optical signal is input into a semiconductor optical amplifier that is tuned to the respective portion of the first bandwidth that corresponds to the subband optical signal. The combination of the partitioned input optical signal and tuned semiconductor optical amplifiers provides improved optical signal transmission performance by reducing polarization dependent gain.

Optical transmission system transmits WDM signal from first node to second node via optical fiber. The optical transmission system includes: first OCM that detects optical power of each wavelength channel of the WDM signal in the first node; second OCM that detects optical power of each wavelength channel of the WDM signal in the second node; first processor that calculates linear SNR of each wavelength channel based on the optical power of each wavelength channel detected by the second OCM; second processor that calculates non-linear SNR of each wavelength channel based on the optical power of each wavelength channel detected by the first OCM; third processor that calculates GSNR for each wavelength channel using the linear SNR and the non-linear SNR; and fourth processor that controls transmission power of each wavelength channel of the WDM signal based on the GSNR of each wavelength channel.

A fiber-optic communication apparatus includes an optical monitor that monitors a WDM signal in. which optical signals of multiple channels are multiplexed, a processor that calculates a control value for controlling an optical power of the WDM signal, based. on a power spectrum detected by the optical monitor, in a unit interval of frequency narrower than a channel bandwidth of the WDM signal, and an optical power adjusting mechanism that adjusts the optical power of the WDM signal in the unit interval of frequency based on the control value.

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).

An optical network communication system utilizes a coherent passive optical network (PON). The system includes an optical line terminal (OLT) having a downstream transmitter and an upstream receiver system configured for time-wavelength division coherent detection. The system further includes a splitter in operable communication with the OLT, and a plurality of optical network units (ONUs) in operable communication with the splitter. Each of the plurality of ONUs is configured to (i) receive downstream coherent burst signals from the OLT, and (ii) transmit at least one upstream burst signal to the OLT. The upstream receiver system further includes a power control module and a local oscillator (LO) configured to generate an optical LO signal The power control module is configured to adaptively control, in real-time, a power level of the optical LO signal.