An optical semiconductor device 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. The optical semiconductor device includes a separate confinement heterostructure layer positioned between the quantum well active layer and the n-type cladding layer. The optical semiconductor device further includes 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. The optical semiconductor device is applied to a ridge-stripe type laser.

A Distributed Feedback Laser (DFB) mounted on a Silicon Photonic Integrated Circuit (Si PIC), the DFB having a longitudinal length which extends from a first end of the DFB laser to a second end of the DFB laser, the DFB laser comprising: an epi stack, the epi stack comprising: one or more active material layers; a layer comprising a partial grating, the partial grating extending from the second end of the DFB laser, only partially along the longitudinal length of the DFB laser such that it does not extend to the first end of the DFB laser; a highly reflective medium located at the first end of the DFB laser; and a back facet located at the second end of the DFB laser.

A reflectivity of an end surface protective film of a semiconductor laser element is made less than or equal to 1% in a wide wavelength range. Semiconductor laser element includes semiconductor stack body having front end surface and rear end surface, and end surface protective film disposed on front end surface of semiconductor stack body. End surface protective film includes first dielectric layer disposed on front end surface and second dielectric layer stacked outside first dielectric layer. Second dielectric layer includes first layer stacked on first dielectric layer, second layer stacked on first layer, and third layer stacked on second layer. For wavelength λ, of a laser beam, refractive index n2 of second layer is higher than refractive index n1 of first layer and refractive index n3 of third layer, and a film thickness of second layer ranges from λ(8n2) to 3λ(4n2) inclusive.

The invention relates to a semiconductor laser comprising a semiconductor layer arrangement, having an active zone for radiation generation, as well as comprising a first resonator mirror, a second resonator mirror and a resonator arranged between the first and the second resonator mirror, which ends in a direction parallel to a main surface of the semiconductor layer arrangement. The semiconductor laser also comprises a first wavelength-selective absorption element which is arranged between the semiconductor layer arrangement and the first resonator mirror.

A quantum-cascade laser element includes: a semiconductor substrate; a semiconductor laminate formed on the semiconductor substrate to include a ridge portion configured to include an active layer having a quantum-cascade structure; an embedding layer including a first portion formed on a side surface of the ridge portion, and a second portion extending from an edge portion of the first portion on a side of the semiconductor substrate along a width direction of the semiconductor substrate; a metal layer formed on a top surface of the ridge portion, on the first portion, and on the second portion; and a dielectric layer disposed between the second portion and the metal layer. The dielectric layer is formed such that a part of the second portion is exposed from the dielectric layer. The metal layer is in contact with the second portion at the part.

A semiconductor light-emitting module according to the present embodiment includes a plurality of semiconductor light-emitting elements each outputting light of a desired beam projection pattern; and a support substrate holding the plurality of semiconductor light-emitting elements. Each of the plurality of semiconductor light-emitting elements includes a phase modulation layer configured to form a target beam projection pattern in a target beam projection region. The plurality of semiconductor light-emitting elements include first and second semiconductor light-emitting elements that are different in terms of at least any of a beam projection direction, the target beam projection pattern, and a light emission wavelength.

An optical system comprising an optoelectronic device having a facet and a coating on the facet. The facet is configured to be in optical communication with at least a first optical medium during a first time period and a second optical medium during a second time period. The first optical medium has a first refractive index and the second optical medium has a second refractive index different from the first refractive index. The coating is configured to provide a first reflectance during the first time period for optical signals in a predetermined wavelength range and to provide a second reflectance during the second time period for optical signals in the predetermined wavelength range wherein the second reflectance is equal to the first reflectance within a negligible margin for optical signals having at least one wavelength in the predetermined wavelength range.

Building blocks are provided for on-chip chemical sensors and other highly-compact photonic integrated circuits combining interband or quantum cascade lasers and detectors with passive waveguides and other components integrated on a III-V or silicon. A MWIR or LWIR laser source is evanescently coupled into a passive extended or resonant-cavity waveguide that provides evanescent coupling to a sample gas (or liquid) for spectroscopic chemical sensing. In the case of an ICL, the uppermost layer of this passive waveguide has a relatively high index of refraction that enables it to form the core of the waveguide, while the ambient air, consisting of the sample gas, functions as the top cladding layer. A fraction of the propagating light beam is absorbed by the sample gas if it contains a chemical species having a fingerprint absorption feature within the spectral linewidth of the laser emission.

An optical device includes a first reflector; a second reflector; an elastic support unit supporting the second reflector; a piezoelectric element on the elastic support unit; a light emitter configured to emit light having an oscillation wavelength; and circuitry configured to output a signal to apply drive voltage to the piezoelectric element to elastically deform the elastic support unit. The deformation of the elastic support unit changes a distance between the first reflector and the second reflector to change the oscillation wavelength of the light emitted from the light emitter.

A semiconductor laser machine includes a semiconductor laser element including a first end face that emits a laser beam and a second end face that is opposite the first end face; a heat sink; and a sub-mount securing the semiconductor laser element to the heat sink. The sub-mount includes a substrate that serves as a thermal stress reliever, a solder layer joined to the semiconductor laser element, and a junction layer formed between the substrate and the solder layer. Compared with the semiconductor laser element, the substrate is extended in a rearward direction that is from the first end face toward the second end face. As for the solder layer and the junction layer, a portion of at least the solder layer is removed behind the second end face.