A method for amplifying an optical seed beam in a fiber laser amplifier system. The method includes frequency modulating the seed beam to a carrier spectral band, amplitude modulating the seed beam that is synchronized with the frequency modulated seed beam, amplifying the seed beam using a pump power beam to provide an output beam where most of the beam power resides in the carrier spectral band, sampling off a sample beam from the output beam, filtering out the carrier spectral band from the sample beam, detecting beam power of the filtered sample beam and providing a beam power signal, and controlling one or more of the frequency modulation of the seed beam, the amplitude modulation of the seed beam and the pump power beam to change an FM modulation depth, an AM modulation depth and/or pump beam power in a manner that reduces the beam power signal.

An optical communication link that includes two nodes interconnected by an optical channel that comprises optical fiber(s), and that is used to communicate an optical signal comprising multiple optical signal wavelengths. The first node provides an optical signal onto the optical channel towards the second node, or receives an optical signal from the optical channel from the second node. A Raman pump provides Raman pump power into the optical fiber of the optical channel to thereby perform Raman amplification of the optical signal in the optical fiber. The second node determines a quality measurement of at least of optical wavelength signals transmitted by the first node to the second node. The second node also transmits information from the quality measurement back to the first node. A controller at the first node controls at least one parameter of the Raman pump in response to this transmitted information.

A laser system including a seed laser and an optical amplification subsystem, receiving an output of the seed laser and providing an amplified laser output, the optical amplification subsystem including a first plurality of amplifier assemblies, each of the first plurality of amplifier assemblies including a second plurality of optical amplifiers, and phase control circuitry including phase modulating functionality associated with each of the first plurality of amplifier assemblies.

An apparatus and a method for stabilizing output of a light source are disclosed. The stabilization device located outside of a light source comprises a stabilization element, and a stabilization controller configured to control a light output from the light source so that a part of the light output and other part of the light cross propagate in the stabilization element.

An apparatus and a method for stabilizing output of a light source are disclosed. The stabilization device located outside of a light source comprises a stabilization element, and a stabilization controller configured to control a light output from the light source so that a part of the light output and other part of the light cross propagate in the stabilization element.

A single loop hardware-based system for producing laser pulses in a microsecond scale operational mode includes a GUI to enable a user to select the operational mode of the system; a laser source for producing one or more laser beam pulses, the laser source being a diode laser pump source module; a DSP which enables and disables a hardware-based FPGA. The FPGA controls the diode pump source module. When a user selects one or more microsecond scale laser sub-pulses on the GUI, the DSP transmits to the FPGA the sub-pulse energy level and the sub-pulse on-time selected by the user on the GUI. A photodetector operatively connected to the hardware-based system measures the power of the laser pulse beam that was transmitted to the photodetector and, in a feedback mode, transmits a feedback signal of that power measurement to the FPGA. The FPGA compares the power of the laser beam measured by the photodetector to the power of the laser beam selected by the user on the GUI. If the power level read by the FPGA is higher than the selected power level, the FGPA decreases the power level to the pumping source module for any subsequent laser pulses; and if the power level read by the FPGA is less than the selected power level, the FGPA increases the power level to the pumping source module for subsequent laser pulses.

A Raman pumping arrangement for amplifying a data optical signal (40) has a Raman pump (12) for generating a Raman pump signal (44;45), an optical supervisory channel receiver (14) for receiving an optical supervisory channel signal (42) an amplification fiber (15) arranged such that the data optical signal (40), the optical supervisory channel signal (42), and the Raman pump signal (44;45) are transmitted therethrough; and a control unit (13) configured for controlling the operation of the Raman pump (12); wherein the control unit (13) is configured for setting the Raman pump (12) in an operation mode or a start-up mode; wherein in the operation mode, the Raman pump (12) provides an operation pumping power (120), and wherein in the start-up mode, the Raman pump (12) provides a start-up pumping power (122).

A control method of the present invention is a control method of controlling a fiber laser including a plurality of LD modules constituting a plurality of groups. The control method includes the steps of: (a) detecting an intensity of laser light outputted from the fiber laser; and (b) controlling a driving current so that, in a case where the intensity of the laser light which intensity has been detected in the step (a) is lower than a predetermined lower limit threshold, a driving current for LD modules in a specific group among the plurality of groups is increased.

A laser system including a seed laser and an optical amplification subsystem, receiving an output of the seed laser and providing an amplified laser output, the optical amplification subsystem including a first plurality of amplifier assemblies, each of the first plurality of amplifier assemblies including a second plurality of optical amplifiers, and phase control circuitry including phase modulating functionality associated with each of the first plurality of amplifier assemblies.

A laser system for generating a series of laser pulses comprising a laser generator that supplies an injection pulse to an amplifier; said amplifier comprising: a gain medium enclosed between a first mirror and a second, output, mirror opposite to said first mirror; and an optical switch set in the proximity of said first mirror; said laser system being characterized in that said amplifier is an unstable laser resonator and said injection pulse is supplied to said laser resonator in synchronism with opening of said optical switch; said series of laser pulses comprises at least one pulse having a duration shorter than or equal to 2 ns and an energy higher than 100 mJ and at least three times higher than the energy of any other pulse of said series of pulses.