In a semiconductor laser according to an embodiment of the present disclosure, a ridge part has a structure in which a plurality of gain regions and a plurality of Q-switch regions are each disposed alternately with each of separation regions being interposed therebetween in an extending direction of the ridge part. The separation regions each have a separation groove that separates from each other, by a space, the gain region and the Q-switch region adjacent to each other. The separation groove has a bottom surface at a position, in a second semiconductor layer, higher than a part corresponding to a foot of each of both sides of the ridge part.

An optical transmitter and a method for driving the optical transmitter include emitting an optical signal using a laser having a lasing cavity with a first section and a second section, performing, using a first heater thermally coupled to the first section, a first temperature control on the first section using a first control signal, and performing, using a second heater thermally coupled to the second section, a second temperature control on the second section using a second control signal. The first temperature control is independent from the second temperature control.

A monolithic laser device assembly 10A in the present disclosure includes a first gain portion 20 having a first end portion 20A and a second end portion 20B, a second gain portion 30 having a third end portion 30A and a fourth end portion 30B, one or multiple ring resonators 40, a semiconductor optical amplifier 50 for amplifying a laser light emitted from the first gain portion 20, and a pulse selector 60 disposed between the first gain portion 20 and the semiconductor optical amplifier 50, in which the ring resonator 40 is optically coupled with the first gain portion 20 and with the second gain portion 30, and laser oscillation is performed on either the first gain portion 20 or the second gain portion 30.

A transmitter unit for emitting radiation into the surrounding area, including at least one semiconductor laser, which has at least one first emitter possessing a first section and a second section; and at least one control unit for controlling the semiconductor laser. The control unit is configured to apply a first supply variable to the first section of the at least one emitter, and to apply a second supply variable differing from the first supply variable, to the second section of the at least one emitter.

A pulse transformer for modifying the amplitude and phase of short optical pulses includes a pulse source and an adaptively controlled stretcher or compressor including at least one fiber Bragg grating (FBG) configured to receive pulses from the pulse source and having a first second-order dispersion parameter (D.sub.21). The pulse transformer further includes at least one optical amplifier configured to receive pulses from the FBG and a compressor configured to receive pulses from the at least one optical amplifier. The compressor has a second second-order dispersion parameter (D.sub.22), an absolute value of the first second-order dispersion parameter (|D.sub.21|) and an absolute value of the second second-order dispersion parameter (|D.sub.22|) that are substantially equal to one another to within 10%.

The present disclosure relates to systems and circuits that may facilitate sub-5 nanosecond laser diode operation. An example system includes a trigger source, a laser diode, a first field effect transistor and a second field effect transistor. The laser diode is coupled to a supply voltage and a drain terminal of the first field effect transistor. A source terminal of the first field effect transistor is coupled to ground and a gate terminal of the first field effect transistor is coupled to the trigger source. A drain terminal of the second field effect transistor is coupled to the supply voltage. A source terminal of the second field effect transistor and a gate terminal of the second field effect transistor are coupled to ground. In an example embodiment, the first field effect transistor and the second field effect transistor comprise gallium nitride (GaN).

A method (700) of biasing a tunable laser (310) during burst-on and burst-off states includes receiving a burst mode signal (514) indicative of the burst-on state or the burst-off state and when the burst mode signal is indicative of the burst-on state: delivering a first bias current (I.sub.GAIN) to an anode of a gain-section diode (590a) disposed on a shared substrate of the tunable laser; and delivering a second bias current (I.sub.PH) to an anode of phase-section diode (590b) disposed on the shared substrate. The second bias current is less than the first bias current. When the burst mode signal transitions to be indicative of the burst-off state, the method also includes delivering the first bias current to the anode of the gain-section diode; and delivering the second bias current to the anode of the phase-section diode wherein the first bias current is less than the second bias current.

A surface-emitting laser includes an active layer; multiple reflectors sandwiching the active layer; and an electrode pair connected to a power supply, through which a current is injected into the active layer. The surface-emitting laser emits at least one laser beam during a current injection period when the current injected into the active layer through the electrode pair during the current injection period is a first current and emits at least one laser beam during a current decrease period when the current injected into the active layer through the electrode pair during the current injection period is a second current exceeding the first current. The current decrease period is after the current injection period. The current injected into the active layer during the current decrease period is lower than the current injected into the active layer during the current injection period.

It is provided a method for fabricating an electroabsorption modulated laser comprising generating a single mode laser section and an electroabsorption modulator section, comprising fabricating at least one n-doped layer of the laser section and at least one n-doped layer of the modulator section; generating an isolating section for electrically isolating at least the n-doped layer of the laser section and the n-doped layer of the modulator section from one another. Generating the isolating section comprises epitaxially growing at least one isolating layer and structuring the isolating layer before the generation of the n-doped layer of the laser section and the n-doped layer of the modulator section.

A system and method for tuning and infrared source laser in the Mid-IR wavelength range. The system and method comprising, at least, a plurality of individually tunable emitters, each emitter emitting a beam having a unique wavelength, a grating, a mirror positioned after the grating to receive at least one refracted order of light of at least one beam and to redirect the beam back towards the grating, and a micro-electro-mechanical systems device containing a plurality of adjustable micro-mirrors.