A light source employed in a coherent Raman scattering (CRS) spectroscopic apparatus or a CRS microscope includes a chromium forsterite laser (CrFL), a variable delay optical path configured to delay one optical pulse of branched optical pulses obtained by dividing an optical pulse from the CrFL according to a power, a highly nonlinear waveguide into which the other optical pulse of the branched optical pulses is input, a first wavelength filter connected to an output of the highly nonlinear waveguide, an ytterbium-doped glass fiber optical amplifier (YbFA) connected to an output of the wavelength filter, and a second wavelength filter connected to an output of the YbFA. The light source includes a one-optical path mode in which two wavelength bands corresponding to Raman scattering wavenumbers to be used for measurement are selected from an output of the variable delay optical path, and a two-optical path mode in which an output of the variable delay optical path and an output of the second wavelength filter are time-synchronized.

Methods and apparatus for receiving a return laser pulse at a detector system having pixels in a pixel array and analyzing a response of the pixels in the pixel array including comparing the response to at least one threshold corresponding to decay of photonic energy of the laser pulse over distance and target reflectivity, wherein the at least one threshold comprises a first threshold corresponding to a low trigger for a pulse generated by a first type of laser and a second threshold corresponding to a high trigger for the pulse generated by the first type of laser. Embodiments can further include generating an alert signal based on the response of the pixels in the pixel array.

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.

A hybrid coherent beam combining (CBC) and spectral beam combining (SBC) fiber laser amplifier system including a beam shaper array assembly and a beam source that provides a plurality of beams having a low fill factor profile. The assembly includes an input beam shaper array having a plurality of rectilinear input cells positioned adjacent to each other that are shaped to cause the beam to expand as it propagates away from the input array to be converted from the low fill factor profile to a high fill factor profile. The assembly further includes an output beam shaper array having a plurality of output cells positioned adjacent to each other that are shaped to cause the beam to stop expanding so that the output array provides a plurality of adjacent beams with minimal overlap and a minimal gap between the beams.

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 fiber optic sensor interrogation system with inbuilt passive power limiting capability based on stimulated Brillouin scattering that provides improved safety performance for use in explosive atmospheres.

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.

A method and system for amplifying optical signals includes generating idler signals for input signals using an optical pump at a first non-linear element (NLE). An intermediate stage including a Raman amplifier performs pump amplification using the output from the first NLE along a single optical path. Optical power monitoring of the input signals may be used for power equalization. The intermediate stage may include a wavelength selective switch for a certain degree of phase modulation. The phase-sensitive amplified signal is generated at a second NLE using the optical pump. Optical power monitoring of the input signals may be used for power equalization and other control functions to achieve low-noise operation.

Fiber laser having a monolithic laser resonator having laser affected zones for providing laser beams having wavelengths below 800 nm and from between 400 nm to 800 nm. Methods of using femtosecond lasers to form fiber Bragg gratings, volume Bragg gratings, space gratings, and laser beam delivery patterns for changing the index of refraction within optical fibers.