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).

An optical fiber connection unit able to efficiently remove heat generated in the optical fiber connection unit. The optical fiber connection unit includes a closed circulation path, through which coolant for eliminating heat generated in the optical fiber connection unit by a laser beam propagating through the optical fiber connection unit circulates, and a coolant circulation device for causing the coolant to flow and circulate in the circulation path.

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.

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.

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 tunable laser array photonic integrated circuit (PIC) is disclosed. The PIC may include an epitaxial structure on a substrate and multiple laser diodes in the epitaxial structure. Each laser diode may operate in a range of wavelengths and may be continuously tunable within the range based at least in part on a temperature of the substrate and a bias current applied to the laser diode. A wavelength-division multiplexer (WDM), configured to receive light from each laser diode, is provided in the epitaxial structure of the PIC. A passband center wavelength of the WDM is selectively temperature tunable by a local heater coupled to the WDM.

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.

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.

A current control device supplies a current to a semiconductor laser in order to output laser light to the semiconductor laser, and includes a current commander and a supplier. The current commander outputs a command value corresponding to a current value by increasing the command value with a lapse of time until reaching a target command value corresponding to a current value for outputting the laser light with a predetermined strength. The supplier supplies a current with a size corresponding to the command value output by the current commander to the semiconductor laser.

To provide an optical module whose power consumption in an ambient temperature range is reduced, and an optical transmission equipment. The optical module includes: a housing; a box type optical subassembly including a bottom portion serving as a heat dissipation face; and a heat conductive member disposed between the bottom portion of the optical subassembly and a bottom portion of the housing. The optical subassembly includes one or a plurality of optical semiconductor devices, and a temperature controller on which the one or plurality of optical semiconductor devices are mounted and which is placed on an inner bottom portion of the optical subassembly. The heat conductive member is disposed only at a portion of the bottom portion of the optical subassembly.