There is provided a light detecting device including: a laser light source generating light source pulse beam; a splitting section splitting the light source pulse beam into excitation beam, first probe beam and second probe beam; a first modulating section executing optical path length modulation that modulates a relative optical path length difference between the excitation beam, and the first probe beam and the second probe beam; a second modulating section phase-modulating the first probe beam; and a detecting section illuminating combined beam, in which the excitation beam, the first probe beam and the second probe beam are multiplexed, onto a sample, and detecting a stimulated Raman scattering signal that is generated.

A fixed input current is provided to a pump laser of an optical pumping block. Further, a first tuning temperature is provided to the pump laser while providing the fixed input current. The first tuning temperature is based on a target band of a pumping beam and causes the pump laser to generate a light beam having a first frequency band that is dictated by the first tuning temperature and the fixed input current. Further, a second tuning temperature is provided to a temperature dependent optical reflector configured to receive the light beam. The second tuning temperature is based on the target band of the pumping beam and causes the optical reflector to reflect light of the light beam that is within a second frequency band that corresponds to the target frequency band. The reflected light beam is emitted into a transmission optical medium configured to carry an optical signal.

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.

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 method for reducing or eliminating bias instability in a SBS laser gyroscope comprises introducing a first pump signal propagating in a CW direction, and a second pump signal propagating in a CCW direction in a resonator; generating a CCW first-order SBS signal and a CW first-order SBS signal in the resonator; increasing a power level of the first pump signal above a threshold level such that the CW first-order SBS signal generates a CCW second-order SBS signal; and increasing a power level of the second pump signal above the threshold level such that the CCW first-order SBS signal generates a CW second-order SBS signal. Above the threshold level, an intensity fluctuation of the first-order SBS signals disappear and their DC power are clamped at substantially the same power level. A Kerr effect bias instability of the SBS laser gyroscope is reduced or eliminated by the clamped first-order SBS signals.

Disclosed herein are methods and systems for configuring a raman amplifier. One exemplary system may be provided with a raman amplifier having a plurality of raman pumps and a controller, and a network administration device. The network administration device generates and deploys a first machine learning model and a second machine learning model to the controller of the raman amplifier. A desired gain profile may be automatically assessed using the first machine learning model to determine raman pump configurations for each of the plurality of raman pumps of the raman amplifier. The raman pump configurations for each of the plurality of raman pumps of the raman amplifier may be processed with the second machine learning model to produce an output gain profile. The determined raman pump configurations are deployed only if the output gain profile and the desired gain profile match to within a margin of error.

Disclosed herein are methods and systems for configuring a raman amplifier. One exemplary system may be provided with a raman amplifier having a plurality of raman pumps and a controller, and a network administration device. The network administration device generates and deploys a first machine learning model and a second machine learning model to the controller of the raman amplifier. A desired gain profile may be automatically assessed using the first machine learning model to determine raman pump configurations for each of the plurality of raman pumps of the raman amplifier. The raman pump configurations for each of the plurality of raman pumps of the raman amplifier may be processed with the second machine learning model to produce an output gain profile. The determined raman pump configurations are deployed only if the output gain profile and the desired gain profile match to within a margin of error.

A seed laser is configured to emit seed laser light. A plurality of optical amplifiers is configured to generate amplified laser light by amplifying the seed laser light. Each of the optical amplifiers is configured to separately direct its respective amplified laser light to a medium without being optically combined within the laser assembly with any of the other amplified laser light emitted by other optical amplifiers in the plurality of optical amplifiers.

A Raman pumping device (10) for amplifying a data optical signal in a fiber optic transmission system, comprising first and second ports (12a, 12b) through which the data optical signal may respectively enter and exit the Raman pumping device (10), a Raman pump source (14) for generating a Raman pump signal, and at least one combiner (16) for combining the Raman pump signal with the data optical signal. The Raman pumping device (10) allows for selectively combining the Raman pump signal generated by the same Raman pump source (14), or at least parts of the same Raman pump source (14) codirectionally or counterdirectionally with the data optical signal.

An optically amplified repeater system includes optical transmission paths, a multi-channel optical amplifier, one or more Raman amplification pumping light sources, and a wavelength multiplexer. The multi-channel optical amplifier includes K simultaneous pumping light sources, N optical amplification media, and one or more optical couplers, and simultaneously amplifies, with the K simultaneous pumping light sources, light intensities of optical signals that pass through the N optical amplification media and propagate through the optical transmission paths. Light intensities of the wavelength band of the optical signals is Raman amplified by the Raman amplification pumping light. A light intensity of the Raman amplification pumping light output from the one or more Raman amplification pumping light sources is determined in accordance with characteristic differences between the optical signals passing through the optical transmission paths.