An optical amplifying system is disclosed. The optical amplifying system includes a thermo-electric cooler (TEC), and a semiconductor laser diode (LD) mounted on the TEC. The semiconductor LD generating a modulated optical signal with a wavelength that depends on the temperature of the LD as controlled by the TEC. The optical amplifying system further includes a semiconductor optical amplifier (SOA) that amplifies the modulated optical signal. A feature of the optical amplifying system is that the temperature of the SOA is higher than that of LD.

A driving and stabilization system for a pump laser, and a pump laser system. The driving and stabilization system includes a constant current stabilization device, a constant temperature stabilization device, a power detection device, an environment detection device, and a control device. The constant current stabilization device includes a voltage comparison circuit, a constant current driving circuit, and a switch protection circuit. The constant temperature stabilization device includes an internal constant temperature stabilization circuit and an external constant temperature stabilization circuit.

Provided is a variable wavelength laser device that achieves phase control of high precision while restraining thermal interference and stably outputs emission light of desired wavelength. The variable wavelength laser device of the present invention includes: an optical amplification means including a low-reflective surface that reflects light of wavelengths other than a predetermined wavelength and emits light of the predetermined wavelength; a wavelength control means for controlling wavelength of light being transmitted through the optical waveguide; a phase control means for controlling phase of light being transmitted through the optical waveguide using heat emitted by a heating means; a reflection means for totally reflecting the inputted light; and a heat dissipation means for restraining transfer of heat emitted by the heating means to regions other than a region in which the phase control means is disposed.

Provided are: a light source module capable of having a reduced packaging area size while ensuring wavelength precision; and a method for manufacturing this light source module. This light source module is provided with a light amplifying means, a wavelength monitoring means for detecting a change in wavelength of light outputted from the light amplifying means, and a reflecting means which is disposed between the light amplifying means and the wavelength monitoring means, and which is for reflecting the light outputted from the light amplifying means toward the wavelength monitoring means.

An optical module and a method of assembling the optical module are disclosed. The optical module comprises a laser unit, a modulator unit, and a detector unit mounted on respective thermo-electric coolers (TECs). The modulator unit, which is arranged on an optical axis of the first output port from which a modulated beam is output, modulates the continuous wave (CW) beam output from the laser unit. On the other hand, the laser unit and the detector unit are arranged on another optical axis of the second output port from which another CW beam is output. The method of assembling the optical module first aligns one of the first combination of the laser unit and the modulator unit with the first output port and the second combination of the laser unit and the detector unit, and then aligns another of the first combination and the second combination.

A wavelength-tunable external cavity laser comprises a semiconductor optical amplifier chip and a laser external cavity, the laser external cavity comprising a grid filter, a phase adjustor and a silicon-based micro-ring chip, the grid filter and the silicon-based micro-ring chip constituting a wavelength-tunable optical filter which implements wavelength tuning by spectral tuning of the grid filter and/or the silicon-based micro-ring chip. A micro-ring filter in the silicon-based micro-ring chip of the tunable external-cavity laser is manufactured by adopting a mature silicon light technology, which can greatly reduce a manufacturing difficulty of the adjustable filter, and reduce the manufacturing cost of a device. An existing external-cavity adjustable technology platform may be used for smooth transition, so as to improve the degree of integration of this type of device and simplify a preparation process.

To provide a laser device capable of detecting overheating (abnormality) of a heat-generating part by detecting a temperature of a cooling member for cooling the heat-generating part. A laser device includes one or a plurality of heat-generating part(s), one or a plurality of cooling member(s) respectively disposed in contact with the one or plurality of heat-generating part(s), the one or plurality of cooling member(s) containing a refrigerant flowing inside, one or a plurality of first temperature detection part(s) respectively disposed on the one or plurality of cooling member(s) to respectively detect temperatures of the one or plurality of cooling member(s), and a monitoring part capable of detecting an abnormality respectively in the one or plurality of cooling member(s) based on temperature information including information on the temperatures detected by the one or plurality of first temperature detection part(s).

A semiconductor laser module includes a semiconductor laser that outputs laser light; an optical fiber that guides the laser light; a lens that couples the laser light, which is output from the semiconductor laser, with the optical fiber; a base that is substantially tabular in shape and that has the semiconductor laser, the optical fiber, and the lens fixed thereon either directly or indirectly; and a housing which houses the base and fixes the base either directly or indirectly. Among faces of the base, a face on a side that is fixed either directly or indirectly to the housing includes a junction plane that is joined to the housing either directly or indirectly, and a detachment plane that is detached to remain unfixed from the housing.

To provide a laser oscillator allowing the use of a plastic lens in a semiconductor laser module for a high-output laser oscillator while being unlikely to reduce the efficiency of coupling to an optical fiber even if a laser output changes. A laser oscillator comprises a semiconductor laser module with multiple semiconductor laser elements. The laser oscillator comprises: multiple lenses in a first group provided in the semiconductor laser module for causing laser beams from the semiconductor laser elements to pass through; and a lens in a second group provided in the semiconductor laser module for causing all beams having passed through the multiple lenses in the first group to pass through. The lenses in the first group are plastic lenses. The lens in the second group is a glass lens.

An optical amplifying system is disclosed. The optical amplifying system includes a thermo-electric cooler (TEC), and a semiconductor laser diode (LD) mounted on the TEC. The semiconductor LD generating a modulated signal with a designed wavelength depending on a temperature thereof that is controlled by the TEC. The optical amplifying system further includes a semiconductor optical amplifier (SOA) that amplifies the modulated optical signal. A feature of the optical amplifying system is that the temperature of the SOA is higher than that of LD.