Provided are a lens, a stem, an LD chip to emit laser light with a beam center directed along a mounting surface of the stem, and a PD chip having a reflective surface formed with a dielectric multilayer film on its surface, reflecting the laser light emitted from the LD chip toward the lens, and measuring an amount of the laser light, wherein the LD chip is provided with a waveguide portion having a tip portion that is formed on a side of a front end face and has a width of 0.5 to 0.7 μm, and having a tapered portion that is connected to the tip portion and becomes narrower toward the tip portion at a gradient of 0.018 to 0.033.

A discrete wavelength tunable laser having an optical cavity which comprises: a reflective semiconductor optical amplifier (SOA); a demultiplexer (Demux) having a single input and a plurality of outputs, the Demux configured to receive the output of the SOA and to produce a plurality of fixed spectral passbands within the gain bandwidth of the SOA; one or more tunable distributed Bragg reflector(s) (DBR(s)) arranged to receive the outputs of the Demux, each tunable DBR configured to select a reflective spectral band within the gain bandwidth of the SOA upon application of a bias current; wherein the SOA forms the back end mirror of the optical cavity; the one or more tunable DBRs form the front end mirror of the optical cavity; and wherein the lasing channel of the discrete wavelength tunable laser is chosen by the overlap of the selected reflective spectral band of one of the one or more tunable DBRs with a fixed spectral passband of the Demux.

This application provides example signal processing apparatus and example signal processing method. One example signal processing apparatus includes a sampling unit, a beam combiner, and an optical resonator. The sampling unit is connected to the beam combiner, and the beam combiner is connected to the optical resonator. The sampling unit is configured to sample an analog signal by using an optical pulse signal to output a sampled optical pulse signal. The beam combiner is configured to combine the sampled optical pulse signal and a multi-wavelength optical signal into a first optical signal. The optical resonator is configured to perform resonance based on the first optical signal to output a second optical signal in the first optical signal, where a wavelength of the second optical signal is equal to a resonant wavelength of the optical resonator.

An apparatus such as an optical modulator includes a buried oxide layer is disposed on a substrate. A microring resonator and an optical waveguide are disposed on the buried oxide layer and within a bonded semiconductor layer. The optical waveguide is optically coupled to the microring resonator and inputs a first optical wave into the microring resonator. An oxide layer is deposited on top of the optical waveguide and the microring resonator. A set of electrodes is disposed adjacent to the microring resonator, and in response to an electrical signal, the set of electrodes modulates the first optical wave into a modulated optical wave of transverse magnetic polarization within the microring resonator and outputs the modulated optical wave to the optical waveguide.

A disclosed semiconductor laser module includes a semiconductor laser device; a waveguide optical function device that has an incidence end on which laser light emitted from the semiconductor laser device is incident and that guides the incident light; and a protrusion that is provided on an extension line of a light path of the laser light emitted from the semiconductor laser device, the extension line extending beyond the incidence end.

An optical apparatus comprises a semiconductor substrate, and a supermode filtering waveguide (SFW) emitter disposed on the semiconductor substrate. The SFW emitter comprises a first optical waveguide, a spacer layer, and a second optical waveguide spaced apart from the first optical waveguide by the spacer layer. The second optical waveguide is evanescently coupled with the first optical waveguide and is configured, in conjunction with the first waveguide, to selectively propagate only a first mode of a plurality of optical modes. The SFW emitter further comprises an optically active region disposed in one of the first optical waveguide and the second optical waveguide.

Provided is a semiconductor laser element including: a resonator structure; and a first reflection film and a second reflection film provided on a non-emission end surface of the resonator structure and an emission end surface of the resonator structure, respectively. Reflectance R of the second reflection film at a gain wavelength satisfies the following relational expression: R1≤R≤R(Oc)×C where R1 is reflectance of the second reflection film when the resonator structure performs laser oscillation with power 1.4 times a minimum value of threshold power which is minimum power for the resonator structure to perform the laser oscillation, R(Oc) is reflectance of the external resonance mirror, and C is a ratio of light, which is reflected by the external resonance mirror and is incident in the resonator structure, to light which is reflected by the external resonance mirror.

The present disclosure relates to index guided semiconductor laser devices supporting wide single lateral mode operation for high power operation. A narrow channel ridge waveguide structure is presented which devices can be configured as single lateral multi-spectral high power semiconductor lasers, single frequency lasers, gain chips and semiconductor amplifiers. More specifically it relates to a means for increasing the lateral mode size over that of conventional index guided structures to increase the average output power typically limed by Catastrophic Optical Damage (COD) at the laser facet or by intensity related effects. This potentially allows the overall laser cavity length to be shortened for a given output power level to stabilize frequency locking with internal or external gratings to improve single frequency operation.

A semiconductor optical device includes an SOI substrate having a waveguide of silicon, and at least one gain region of a group III-V compound semiconductor having an optical gain bonded to the SOI substrate. The waveguide has a bent portion and multiple linear portions extending linearly and connected to each other through the bent portion. The gain region is disposed on each of the multiple linear portions.

A semiconductor laser light-emitting structure includes a semiconductor laser light-emitting structure having a vertical-cavity surface-emitting laser structure and configured to emit light having a first wavelength, and a wavelength converter including a metasurface and monolithically formed with the semiconductor laser light-emitting structure on a light output side of the semiconductor laser light-emitting structure, wherein the metasurface is configured to non-linearly convert the light having the first wavelength into light having a second wavelength.