An optical semiconductor device includes an optical semiconductor chip in which at least one optical element is formed in a semiconductor substrate, and an extended wire pattern that is connected to a first electrode and a second electrode of the optical element and that extends outside the optical semiconductor chip. The first electrode and the second electrode of the optical semiconductor device are formed on the front surface side of the optical semiconductor chip, and the extended wire pattern is disposed on the front surface of the optical semiconductor chip or disposed at a position apart from the front surface.

Disclosed are a wavelength-selectable laser diode and an optical communication apparatus including the same. The wavelength-selectable laser diode includes a substrate, which includes a gain region, a tuning region spaced apart from the gain region, and a phase adjusting region between the tuning region and the gain region, a waveguide layer on the substrate, a clad layer on the waveguide layer, and gratings disposed on the substrate or the clad layer in the gain region and the tuning region.

A quantum cascade laser includes a first and a second mesa waveguides disposed on a substrate, a first electrode, a second electrode, and a current blocking region disposed burying the first and second mesa waveguides. The first and second mesa waveguides extend in a first direction. The first and second mesa waveguides are arranged apart from each other by a distance in a second direction intersecting with the first direction. The current blocking region has a first portion disposed between the first and second mesa waveguides and a second portion disposed on the first portion. The end of the first electrode and the end of the second electrode are facing each other in the second direction. The second portion protrudes from a reference plane which includes a surface of the end of the first electrode and extends in the first and second directions.

The optical amplifier has an inhomogeneously broadened gain material capable of generating a plurality of ensemble gains. A first optical filter and a second optical filter are provided in the photonic integrated circuit. The apparatus has a first laser cavity which includes the optical amplifier, the first optical filter optically coupled to each other and at least two mirrors. The apparatus has a second laser cavity which includes the optical amplifier, the second optical filter optically coupled to each other and at least two mirrors. The first optical filter is tunable to a respective first ensemble gain generated by the optical amplifier and the second filter is tunable to a respective second ensemble gain generated by the optical amplifier; and the second ensemble gain is different from the first ensemble gain. A laser source and an optical transmitter are also disclosed.

A grating emitter method and system for modulating the polarization of an optical beam, such as one for transmission through free-space or use in an atomic clock.

Disclosed herein is a spectroscopy device incorporating a mid-infrared laser. In one particular embodiment a spectroscopy device is provided including: a substrate; a single mode laser positioned on the substrate; a single mode detector positioned opposite to the single mode laser on the substrate. A gap is formed between the single mode laser and the single mode detector and a substance is positioned in the gap. The single mode laser is configured to output a tunable narrow wavelength of radiation towards the detector and when the single mode laser outputs a wavelength of radiation overlapping one of the substance's rotational-vibrational energy levels, the substance at least partially absorbs the radiation. The single mode detector is configured to measure the amount of narrow wavelength radiation that is not absorbed by the substance between the single mode detector and the single mode laser.

A wavelength-multiplexed light transmission module according to the present invention includes a plurality of lasers that respectively emit a plurality of laser beams having different wavelengths, a lens radially emitting the plurality of laser beams, a bandpass filter that has a transmission center wavelength which is shorter as an incident angle is larger, and a mirror for reflecting the plurality of laser beams, wherein the plurality of laser beams are incident to the bandpass filter such that the incident angle of a laser beam is larger as the laser beam has a shorter wavelength, whereby the plurality of laser beams are transmitted through the bandpass filter, and an inclination angle of the mirror with respect to the bandpass filter is provided such that the plurality of laser beams transmitted through the bandpass filter are reflected by the bandpass filter and the mirror to be multiplexed with one another.

A semiconductor structure includes a group IV substrate and a patterned group III-V device over the group IV substrate. A blanket dielectric layer is situated over the patterned group III-V device. A contact metal is situated within the blanket dielectric layer and an interconnect metal is situated over the blanket dielectric layer. The blanket dielectric layer can be substantially planar. The contact metal and the interconnect metal can be electrically connected to the patterned group III-V device. The patterned group III-V device can be optically and/or electrically connected to group IV devices in the group IV substrate.

A light source based on an optical frequency mixer is disclosed. The light source has a first laser for emitting light at a first optical frequency, and a plurality of second lasers for emitting light at different second optical frequencies. The optical frequency mixer provides output light beams at mixed optical frequencies of the first and second lasers. Wavelength of output light beams may be tuned by tuning wavelength of any of the first or second lasers. In this manner, RGB wavelength-tunable light sources may be constructed based on red or near-infrared lasers. The wavelength tunability of the output light beams may be used to angularly scan or refocus the light beams.

A semiconductor photonic device includes a first cladding layer formed on a substrate formed with Si, a semiconductor layer formed on the first cladding layer, and a second cladding layer formed on the semiconductor layer. In the semiconductor layer, an active layer, and a p-type layer and an n-type layer disposed in contact with the active layer while sandwiching the active layer in a planar view are formed. A p-type electrode is electrically connected to the p-type layer, and an n-type electrode is electrically connected to the n-type layer. The active layer is formed in a core shape extending in a predetermined direction. This semiconductor photonic device also includes an optical coupling layer that is buried in the first cladding layer in such a manner as to be optically coupled to the active layer, and is formed in a core shape extending along the active layer.