A system for communicating supervisory information between amplifier nodes in an optical communication network utilizes modulation of an included pump source to superimpose the supervisory information on data signals (typically customer data signals) propagating between the amplifier nodes transmitted customer signals. The modulated pump appears as a modulated envelope on the amplified data signal exiting the amplifier node, and may be recovered by suitable demodulation components located at the second node (i.e., the destined receiver of the supervisory information). The supervisory information may include monitoring messages, provisioning data, protocol updates, etc., and is utilized as an input to an included modulator, which then forms a drive signal for the pump controller.

An optical amplifier is provided which can suppress, without measuring signal beam power at individual wavelengths, wavelength-dependence of gain with respect to a signal beam into which multiple signal beams having respective wavelengths different from each other are multiplexed. The optical amplifier (100) according to the present invention can suppress wavelength-dependence of gain by giving loss in accordance with a linear-loss slope to an amplified signal beam. The optical amplifier is provided with a variable tilt equalizer (11) for varying a loss slope value representing the slope of the loss slope and a tilt control unit (22) for controlling a loss slope value of the variable tilt equalizer.

A laser apparatus includes a light source configured to output excitation light, an optical resonator in which laser medium. is excited by the excitation light, the optical resonator being configured to output laser beam, a temperature regulator configured to adjust temperature of the light source to a standard temperature, an optical detector configured to detect output power of the laser beam, and a controller configured to change the standard temperature based on the detected output power of the laser beam.

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 wavelength-variable laser 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; a separate confinement heterostructure layer positioned between the quantum well active layer and the n-type cladding layer; and 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.

A laser light-source apparatus includes: a fiber amplifier and a solid-state amplifier to amplify pulse light output from a seed light source serving as a first light source; a nonlinear optical element to perform wavelength conversion on the pulse light output from the solid-state amplifier; an optical switching element to permit or stop propagation of the pulse light from the fiber amplifier to the solid-state amplifier; a second light source disposed on an upstream side of the solid-state amplifier and is configured to output laser light able to be combined with the pulse light output from the seed light source; and a control unit to control the optical switching element in such a manner that the propagation of light is stopped and to perform control in such a manner that the second light source oscillates, at least in an output period of the pulse light from the seed light source.

Described herein are methods for developing and maintaining pulses that are produced from compact resonant cavities using one or more Q-switches and maintaining the output parameters of these pulses created during repetitive pulsed operation. The deterministic control of the evolution of a Q-switched laser pulse is complicated due to dynamic laser cavity feedback effects and unpredictable environmental inputs. Laser pulse shape control in a compact laser cavity (e.g., length/speed of light<?1 ns) is especially difficult because closed loop control becomes impossible due to causality. Because various issues cause laser output of these compact resonator cavities to drift over time, described herein are further methods for automatically maintaining those output parameters.

A radiation amplifying system comprising a laser active medium for amplifying a radiation field and an optical assembly which defines an optical path for a pumping radiation field with which the laser active medium is optically pumped. The optical path comprises a plurality of branches and the optical assembly comprises at least two focusing units and a deflection arrangement. The laser active medium is spatially arranged between the at least two focusing units, and the focusing units define several pumping branches of the optical path for focusing the pumping radiation field which propagates along the optical path onto a pumping area in the laser active medium. Several deflection units of the deflection arrangement define respective deflection branches of the optical path for connecting the several pumping branches. The optical path comprises at least one correction branch for correcting at least one mismatch in the optical assembly to a focusing condition.

Ultrashort pulsed laser systems are described. In one example, a pulsed laser system includes a source laser configured to emit a pulsed source laser beam, a splitter configured to split the source laser beam into first and second input laser beams, a first amplifier module configured to amplify the first input laser beam using chirped pulse amplification (CPA) and to produce, at a first output port, a first output laser beam in a first spectral range based on soliton self-frequency shift (SSFS) in the first amplifier module, a second amplifier module configured to amplify the second input laser beam using CPA and to produce an intermediate beam based on SSFS in the second amplifier module, and a mid-infrared fiber configured to receive the intermediate beam and to produce, at a second output port, a second output laser beam in a second spectral range based SSFS in the mid-infrared fiber.

A light source device includes: a fiber laser including an excitation light source and configured to output pulsed light generated according to excitation light from the excitation light source; a fiber amplifier configured to receive the pulsed light output from the fiber laser, amplify the pulsed light, and output the amplified pulsed light, a wavelength shift fiber configured to receive the pulsed light output from the fiber amplifier, shift a wavelength of the pulsed light, and output the pulsed light; an output fiber configured to receive the pulsed light output from the wavelength shift fiber, and output the pulsed light to an outside; a light detection element configured to detect, in the output fiber, the pulsed light having passed through at least the wavelength shift fiber; and a control unit configured to control a drive current of the excitation light source.