Described herein are photonic integrated circuits (PICs) comprising a semiconductor optical amplifier (SOA) to output a signal comprising a plurality of wavelengths, a sensor to detect data associated with a power value of each wavelength of the output signal of the SOA, a filter to filter power values of one or more of the wavelengths of the output signal of the SOA, and control circuitry to control the filter to reduce a difference between a pre-determined power value of each filtered wavelength of the output signal of the SOA and the detected power value of each filtered wavelength of the output signal of the SOA.

A slope gain equalizer that corrects a slope of a gain characteristic of an optical signal in a predetermined wavelength bandwidth. An interference filter, which allows insertion losses in a predetermined wavelength region to be inclined in opposite directions between a transmitting direction and a reflecting direction from a short wavelength side to a long wavelength side, is arranged between a dual-core fiber collimator and a single-core fiber collimator facing each other on an optical axis. An optical signal of a predetermined bandwidth inputted from a first or second optical fiber held by the dual-core fiber collimator is reflected by the interference filter and outputted from the second or the first optical fiber. An optical signal inputted from a third optical fiber held by the first optical fiber or the single-core fiber collimator is transmitted through the interference filter and outputted from the third or the first optical fiber.

A slope gain equalizer that corrects a slope of a gain characteristic of an optical signal in a predetermined wavelength bandwidth. An interference filter, which allows insertion losses in a predetermined wavelength region to be inclined in opposite directions between a transmitting direction and a reflecting direction from a short wavelength side to a long wavelength side, is arranged between a dual-core fiber collimator and a single-core fiber collimator facing each other on an optical axis. An optical signal of a predetermined bandwidth inputted from a first or second optical fiber held by the dual-core fiber collimator is reflected by the interference filter and outputted from the second or the first optical fiber. An optical signal inputted from a third optical fiber held by the first optical fiber or the single-core fiber collimator is transmitted through the interference filter and outputted from the third or the first optical fiber.

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.

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.

An optical repeater device includes an amplifier module and a monitoring control circuit. The optical amplifier module includes an amplifier optical circuit including a plurality of amplification cores that amplify signal light propagating through different cores, and an optical amplifier control circuit that receives detection results from optical detectors at a plurality of signal light waveguide points of the amplifier optical circuit and generates a control signal directed to an excitation light source. The monitoring control circuit includes a reception unit that receives monitoring control channel light, a transmission unit that transmits the monitoring control channel light, an information determination unit that determines whether the monitoring control information received from the reception unit is for its own device or for another device, and a monitoring control unit that receives monitoring control information from the other device via the reception unit and the information determination unit and transmits the monitoring control information of its own device to the other device via the transmission unit and the information determination unit.

Embodiments of this application provide an OLT, an ONU, and a system. In a downlink direction, the first OLT is configured to convert received downlink data packets of M1 paths into one downlink optical signal whose wavelength is λo, and the first ONU is configured to receive the downlink optical signal, and output a target user data packet after processing the downlink optical signal. In an uplink direction, the first ONU is configured to convert received uplink data packets into an uplink optical signal whose wavelength is λi, and the first OLT is configured to receive a plurality of uplink optical signals of different wavelengths, and output user data packets of a corresponding quantity of paths after processing.

Embodiments of this application provide an OLT, an ONU, and a system. In a downlink direction, the first OLT is configured to convert received downlink data packets of M1 paths into one downlink optical signal whose wavelength is λo, and the first ONU is configured to receive the downlink optical signal, and output a target user data packet after processing the downlink optical signal. In an uplink direction, the first ONU is configured to convert received uplink data packets into an uplink optical signal whose wavelength is λi, and the first OLT is configured to receive a plurality of uplink optical signals of different wavelengths, and output user data packets of a corresponding quantity of paths after processing.

A plastic optical fiber communication system includes a light source that emits a first signal having a first wavelength in a visible light spectrum, the first signal being encoded with information at a high data-rate of 0.1 to 10 Gbit/s; a pump laser system that emits a pump laser light having a second wavelength, different from the first wavelength; a perovskite-doped optical fiber excited by the pump laser light to generate an amplified spontaneous emission spectrum that encompasses the first wavelength so as to receive and amplify the first signal for generating an amplified output signal having the first wavelength; and a photodetector optically coupled to the perovskite-doped optical fiber, and configured to receive the amplified output signal at the high data-rate of 0.1 to 10 Gbit/s. The amplified output signal is encoded with the information.

A plastic optical fiber communication system includes a light source that emits a first signal having a first wavelength in a visible light spectrum, the first signal being encoded with information at a high data-rate of 0.1 to 10 Gbit/s; a pump laser system that emits a pump laser light having a second wavelength, different from the first wavelength; a perovskite-doped optical fiber excited by the pump laser light to generate an amplified spontaneous emission spectrum that encompasses the first wavelength so as to receive and amplify the first signal for generating an amplified output signal having the first wavelength; and a photodetector optically coupled to the perovskite-doped optical fiber, and configured to receive the amplified output signal at the high data-rate of 0.1 to 10 Gbit/s. The amplified output signal is encoded with the information.