A fiber coupled modular laser system comprises a laser oscillator, at least one fiber pre-amplifier, and at least one free space solid state power amplifier. The output of the laser oscillator is fiber coupled with the input of the at least one fiber pre-amplifier or the at least one free space solid state power amplifier. The output or the input of the at least one fiber pre-amplifier is fiber coupled with the input or the output of the at least one free space solid state power amplifier.

A method for realizing precise gain control for a hybrid fibre amplifier, and a hybrid fibre amplifier, in which by an erbium-doped fibre amplifier firstly outputting a constant power, a comparable source signal optical power is provided for a raman fibre amplifier of a next stage. A feedback for the gain control may be formed by comparing a source signal optical power calculated after starting pumping of the Raman fibre amplifier and a source signal optical power detected after pumping stops, thereby greatly improving gain control precision of the Raman fibre amplifier. Moreover, the erbium-doped fibre amplifier parts of all the hybrid fibre amplifiers may simultaneously output a constant optical power, and the Raman amplifier parts of all the hybrid fibre amplifiers may simultaneously start calibration, so that the time for starting operation of the entire system may be improved greatly.

A laser system according to an embodiment of the present invention includes an oscillation unit to generate a laser output, a connection unit to connect the oscillation unit with an optical fiber loop, an amplifying unit to amplify the laser output on the optical fiber loop, a conversion unit disposed on the optical fiber loop to convert pulsed wave laser output into continuous wave laser output, and an output unit disposed between the connection unit and the conversion unit to split a part of the laser output toward the conversion unit. The system for generating a high output pulsed wave laser and converting the pulsed wave laser into a continuous wave laser may be implemented in a simple structure and small size with high stability and high reproducibility. In addition, a high output laser may be obtained. Also, since conversion from the pulsed wave into the continuous wave is easy, both of the high output pulsed wave and the high output continuous wave may be obtained as necessary.

A hybrid fiber amplifier and method of adjusting gain and gain slope of thereof. The hybrid fiber amplifier comprises: RFA and EDFA that does not comprise variable optical attenuator. The RFA comprises pump signal combiner, pump laser group, out-of-band narrow-band filter, and photodetector. The EDFA comprises input coupler, erbium-doped fiber, output coupler, input photodetector, and output photodetector that are connected in sequence. The hybrid fiber amplifier also comprises control module that coordinates and controls EDFA and/or RFA to adjust gain and/or the gain slope based on desired amplification requirements. The EDFA and/or RFA can be coordinated and controlled by using the control module to achieve desired amplification effect. In addition, the EDFA does not comprise the variable optical attenuator, which avoids problems caused by the variable optical attenuator. The hybrid fiber amplifier and method of adjusting gain and gain slope thereof are applicable to technical field of optical communications.

Aspects of the present disclosure are directed to methods and apparatuses for generating laser light. As may be implemented in accordance with one or more embodiments, laser light is generated at a laser light source and is modulated in response to a frequency modulation signal, to generate a plurality of different wavelengths of laser light. The frequency modulation signal is generated, for each particular one of the wavelengths of laser light, at a respective seeding frequency corresponding to the particular one of the wavelengths in which the seeding frequency is different for each of the different wavelengths. Such an approach may, for example, involve generating the frequency modulation signal with a frequency generator circuit and using the frequency modulation signal to control an electro-optical modulator for modulating the wavelength of the laser light.

A laser that emits light at all available frequencies distributed throughout the spectral bandwidth or emission bandwidth of the laser in a single pulse or pulse train is disclosed. The laser is pumped or seeded with photons having frequencies distributed throughout the superunitary gain bandwidth of the gain medium. The source of photons is a frequency modulated photon source, and the frequency modulation is controlled to occur in one or more cycles timed to occur within a time scale for pulsing the laser.

In one embodiment, a lidar system includes a multi junction light source configured to emit an optical signal. The multi junction light source includes a seed laser diode configured to produce a seed optical signal and a multi junction semiconductor optical amplifier (SOA) configured to amplify the seed optical signal to produce the emitted optical signal. The lidar system also includes a receiver configured to detect a portion of the emitted optical signal scattered by a target located a distance from the lidar system. The lidar system further includes a processor configured to determine the distance from the lidar system to the target based on a round-trip time for the portion of the scattered optical signal to travel from the lidar system to the target and back to the lidar system.

An optical amplification device includes a first Raman amplifier outputs a first excitation light to a transmission line in a same direction as a signal light, and a second Raman amplifier outputs a second excitation light to the transmission line in an opposite direction to the signal light. The first Raman amplifier includes a first detector detects a first power of a first transmitted light transmitted through a first optical filter. The second Raman amplifier includes a second detector detects second power of a second transmitted light transmitted through a second optical filter. The first Raman amplifier stops output of the first excitation light when the first power is higher than a threshold. The second Raman amplifier stops output of the second excitation light when the second power is reduced from power of the first excitation light transmitted through the second optical filter.

A laser processing method of performing laser processing on a transparent material that is transparent to ultraviolet light by using a laser processing system includes: performing relative positioning of a transfer position of a transfer image and the transparent material in an optical axis direction of a pulse laser beam so that the transfer position is set at a position inside the transparent material at a predetermined depth ΔZsf from a surface of the transparent material in the optical axis direction; and irradiating the transparent material with the pulse laser beam having a pulse width of 1 ns to 100 ns inclusive and a beam diameter of 10 μm to 150 μm inclusive at the transfer position.

Embodiments discussed herein refer to LiDAR systems and methods that enable substantially instantaneous power and frequency control over fiber lasers. The systems and methods can simultaneously control seed laser power and frequency and pump power and frequency to maintain relative constant ratios among each other to maintain a relatively constant excited state ion density of the fiber laser over time.