A method for tuning an emission wavelength of a laser device, including: acquiring a drive condition of a wavelength tunable laser diode to make the wavelength tunable laser diode oscillate at a wavelength from a memory; driving a first thermo-cooler and a first heater based on the drive condition of the wavelength tunable laser diode; determining whether respective control values of the first thermo-cooler and the first heater are reached within a first range of target values; and driving a gain region after the control values have been reached within the first range.

Single-mode quantum cascade semiconductor lasers are provided. The lasers comprise a laser element, the laser element comprising a quantum cascade active layer; an upper cladding layer over the quantum cascade active layer; and a lower cladding layer under the quantum cascade active layer, wherein the quantum cascade active layer, the upper cladding layer and the lower cladding layer define a guided optical mode. The quantum cascade active layer and the upper and lower cladding layers are shaped in the form of a ridge structure having a front face, a back face opposite the front face, and a lasing face through which laser emission exits the ridge structure, the ridge structure configured such that the laser emission has a single-lobe, far-field beam pattern from the ridge structure comprising certain sections, including tapered sections, collateral sections, or both.

A guide transition device including a light source designed to generate a light beam, a light input port on a first plane and coupled to receive the light beam from the light source, a light output port on a second plane different than the first plane, the light output port designed to couple a received light beam to output equipment and plane shifting apparatus coupled to receive the light beam from the light input port on the first plane and to shift or transfer the light beam to the second plane. The plane shifting apparatus including one or more digital gratings each designed to deflect the light beam approximately ninety degrees. The plane shifting apparatus is coupled to transfer the light beam to the light output port on the second plane.

Disclosed is a current-injection organic semiconductor laser diode comprising a pair of electrodes, an optical resonator structure, and one or more organic layers including a light amplification layer composed of an organic semiconductor, which has a sufficient overlap between the distribution of exciton density and the electric field intensity distribution of the resonant optical mode during current injection to emit laser light.

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.

The embodiments herein describe a single-frequency laser source (e.g., a distributed feedback (DFB) laser or distributed Bragg reflector (DBR) laser) that includes a feedback grating or mirror that extends along a waveguide. The grating may be disposed over a portion of the waveguide in an optical gain region in the laser source. Instead of the waveguide or cavity being linear, the laser includes a U-turn region so that two ends of the waveguide terminate at the same facet. That facet is coated with an anti-reflective (AR) coating.

An optical semiconductor apparatus includes: semiconductor laser devices having different emission wavelengths and grouped into at least a first group and a second group; and an arrayed waveguide grating connected to the semiconductor laser devices of the first and second groups and configured to combine laser light beams radiating from the semiconductor laser devices into a same point. The arrayed waveguide grating is configured to combine laser light beams from the semiconductor laser devices belonging to the first group into the same point by diffraction in a first diffraction order in the arrayed waveguide grating, and combine laser light beams from the semiconductor laser devices belonging to the second group into the same point by diffraction in a second diffraction order different from the first diffraction order, in the arrayed waveguide grating.

The embodiments herein describe a single-frequency laser source (e.g., a distributed feedback (DFB) laser or distributed Bragg reflector (DBR) laser) that includes a feedback grating or mirror that extends along a waveguide. The grating may be disposed over a portion of the waveguide in an optical gain region in the laser source. Instead of the waveguide or cavity being linear, the laser includes a U-turn region so that two ends of the waveguide terminate at the same facet. That facet is coated with an anti-reflective (AR) coating.

A guide transition device including a light source designed to generate a light beam, a light input port on a first plane and coupled to receive the light beam from the light source, a light output port on a second plane different than the first plane, the light output port designed to couple a received light beam to output equipment and plane shifting apparatus coupled to receive the light beam from the light input port on the first plane and to shift or transfer the light beam to the second plane. The plane shifting apparatus including one or more digital gratings each designed to deflect the light beam approximately ninety degrees. The plane shifting apparatus is coupled to transfer the light beam to the light output port on the second plane.

A structure of distributed feedback (DFB) laser includes a grating layer having a phase-shift grating structure and a gratingless area. In addition, both side-surfaces of the DFB laser are coated with anti-reflection coating to improve SMSR and to obtain good slope efficiency (SE). The grating layer is divided by the phase-shift grating structure in a horizontal direction into a first grating area and a second grating area adjacent to a laser-out surface of the DFB laser. The phase-shift grating structure provides a phase-difference distance, such that a shift of phase exists between the micro-grating structures located within the first grating area and the other micro-grating structures located within the second grating area. The gratingless area located within the second grating area contains no micro-grating structure, and moreover, the gratingless area will not change the phase of the micro-grating structures located within the second grating area.