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.

A line narrowing gas laser device includes an actuator changing a center wavelength of pulse laser light, and a processor controlling the actuator. The processor reads parameters including a number of irradiation pulses of pulse laser light to be radiated to one location of an irradiation receiving object, a shortest wavelength, and a longest wavelength; sets a first pattern with which the center wavelength is changed to approach the longest wavelength from the shortest wavelength and a second pattern with which the center wavelength is changed to approach the shortest wavelength from the longest wavelength such that at least one of the first pattern and the second pattern when the number of irradiation pulses is an even number is different from corresponding one when the number of irradiation pulses is an odd number; and controls the actuator so that the first pattern and the second pattern are alternately performed.

Disclosed herein are methods and systems configuring a raman amplifier. One exemplary system may be provided with an optical amplifier deployed in an optical network, the optical amplifier having a plurality of raman pumps configured to obtain a desired gain profile. An actual gain profile and a raman pump configuration of each of the plurality of raman pumps may be processed by a network administration device using a first machine learning model to produce a combined optical transmission segment attribute representing attributes of an optical segment of the optical network. The combined optical transmission segment attribute and the desired gain profile may be processed with a second machine learning model to produce corrected raman pump configurations for each of the plurality of raman pumps of the raman amplifier. The corrected raman pump configurations may be used to configure each of the plurality of raman pumps of the raman amplifier.

Disclosed are embodiments for multi-band pumping of a doped fiber source. The doped fiber source has a first absorption band and a second absorption band that is different from the first absorption band. In some embodiments, a first laser pump generates a first pump power in a first pump band corresponding to the first absorption band that is generated. A second laser pump generates a second pump power in a second pump band corresponding to the second absorption band. The second pump band is different from the first pump band. The first and second pump power is simultaneously applied to the doped fiber source.

Example optical amplification apparatus and example signal amplification methods are provided. One example optical amplification apparatus is connected to an optical fiber. The optical amplification apparatus includes a first pump laser and a first gain medium. The first pump laser is configured to emit first pump light. The first gain medium is configured to receive the first pump light and first multi-channel optical signals from the optical fiber; and perform gain amplification on the first multi-channel optical signals based on the first pump light, where the first pump light overlaps each of the first multi-channel optical signals in the first gain medium.

A Raman amplifier includes a first light source that outputs a primary pumping light, which propagates in a same direction as a propagation direction of a signal light, to an optical transmission line for Raman amplification, a second light source that outputs a secondary pumping light, which pumps and amplifies the primary pumping light and propagates in the same direction as the propagation direction, to the optical transmission line, and a control unit that controls a gain for the signal light by adjusting power of the secondary pumping light.

A light source for Raman amplification to Raman-amplify signal light includes: plural incoherent light sources that output incoherent light; plural pumping light sources that output second-order pumping light; an optical fiber for Raman amplification to Raman-amplify the incoherent light with the second-order pumping light, and outputs the amplified incoherent light; and an output unit connected to the optical transmission fiber, receiving the amplified incoherent light, and outputting the amplified incoherent light as first-order pumping light having a wavelength that Raman-amplifies the signal light to the optical transmission fiber.

An optical semiconductor device outputting a predetermined wavelength of laser light includes a quantum well active layer positioned between a p-type cladding layer and an n-type cladding layer in thickness direction. The optical semiconductor device includes a separate confinement heterostructure layer positioned between the quantum well active layer and the n-type cladding layer. The optical semiconductor device further includes an electric-field-distribution-control layer positioned between the separate confinement heterostructure layer and the n-type cladding layer and configured by at least two semiconductor layers having band gap energy greater than band gap energy of a barrier layer constituting the quantum well active layer. The optical semiconductor device is applied to a ridge-stripe type laser.

A tunable microwave source based on dual-wavelength lasing of a single optical whispering gallery microcavity includes a dual-wavelength laser having the single optical whispering gallery microcavity for generating dual-wavelength lasing with adjustable spacing, narrow linewidth and low threshold; an optical fiber or waveguide amplifier for optical signal amplification; an optical filter for optical signal and noise filtration; and a high-speed detector for generating a tunable microwave signal with narrow bandwidth. The dual-wavelength laser includes a pump source, the optical whispering gallery microcavity, an optical waveguide or a tapered optical fiber, a microcavity substrate, and a gold electrode pair. The frequency spacing of the dual-wavelength lasing is tuned by adjusting the external voltage of the gold electrode pair.

An apparatus includes a remote optically pumped amplifier (ROPA). The ROPA includes a bypass filter configured to receive an optical signal and first pump power and to separate the optical signal and the first pump power. The ROPA also includes an amplifier configured to receive the optical signal from the bypass filter and to amplify the optical signal. The ROPA further includes an optical combiner/multiplexer configured to receive the first pump power from the bypass filter, receive at least second and third pump powers, combine at least two of the first, second and third pump powers, and provide different pump powers or combinations of pump powers to different locations within the ROPA to feed the amplifier.