An optical device includes: lasers output first light from a front-end side and output second light from a rear-end side; an optical multiplexer circuit multiplex respective rays of the first light, to thereby send out output light; waveguides guide respective rays of the second light toward one end face of the optical device; and light detectors receive respective rays of reflected light that are due to reflection of the respective rays of the second light after being guided by the waveguides, on the one end face or on respective inclined end faces in concave portions formed on that one end face. The light detector is located between the rear-end side of the laser and the one end face or the inclined end face, and the second light is outputted diagonally relative to a perpendicular line with respect to the one end face or the inclined end face.

A tunable or swept laser architecture that is appropriate for swept source optical coherence tomography and other applications including spectroscopy employing a cat's-eye configuration with a preferably transmissive tilt tuned interference thin film filter.

An apparatus having a waveguide and a freeform collimating lens. The waveguide is characterized by a waveguide axis and a planar end having a normal axis that is inclined at an end angle that is greater than 0 degrees with respect to the waveguide axis. The freeform collimating lens collimates light leaving the planar end of the waveguide into a collimated light beam characterized by a beam direction that is parallel to the waveguide axis. The apparatus inhibits reflections from the planar end of the waveguide from propagating back down the waveguide while providing a collimated light beam having a direction parallel to the axis of the waveguide.

A method for improving wide-band wavelength-tunable laser. The method includes configuring a gain region between a first facet and a second facet and crosswise a PN-junction with an active layer between P-type cladding layer and N-type cladding layer. The method further includes coupling a light excited in the active layer and partially reflected from the second facet to pass through the first facet to a wavelength tuner configured to generate a joint interference spectrum with multiple modes separated by a joint-free-spectral-range (JFSR). Additionally, the method includes configuring the second facet to have reduced reflectivity for increasing wavelengths. Furthermore, the method includes reconfiguring the gain chip with an absorption layer near the active layer to induce a gain loss for wavelengths shorter than a longest wavelength associated with a short-wavelength side mode. Moreover, the method includes outputting amplified light at a basic mode via the second facet.

An optical device includes a light-emitting element; an electronic circuit chip; a substrate on which the light-emitting element and the electronic circuit chip are mounted; a first electrode formed on a first mounting surface of the light-emitting element on the substrate; and a second electrode formed on a second mounting surface of the electronic circuit chip on the substrate. The first electrode and the second electrode have the same structure.

A narrow-linewidth tunable external cavity laser includes, sequentially arranged along an optical path, a laser gain chip, a collimating lens, a bandpass filter, a tunable filter, and an output cavity surface. The laser gain chip includes a first end surface and a second end surface positioned along the optical path. The first end surface is further away from the collimating lens and is coated with a highly reflective film to form an external cavity with the output cavity surface.

A QCL may include a substrate, an emitting facet, and semiconductor layers adjacent the substrate and defining an active region. The active region may have a longitudinal axis canted at an oblique angle to the emitting facet of the substrate. The QCL may include an optical grating being adjacent the active region and configured to emit one of a CW laser output or a pulsed laser output through the emitting facet of substrate.

Provided is a semiconductor chip that can reduce the man-hours for mounting on an optical module, a subcarrier, or the like, and reducing the dedicated area of the subcarrier or the like. The semiconductor chip includes a waveguide that is terminated inside at an output end portion from which light is emitted, without contacting an emission end face, and a window region made of a bulk semiconductor and disposed between the waveguide and the emission end face, wherein the semiconductor chip is provided with an open groove formed in the output end portion so that the emission end face is a side wall formed by etching.

An optoelectronic semiconductor device comprises a plurality of laser devices. Each of the laser devices is configured to emit electromagnetic radiation. The laser devices are horizontally arranged. A first laser device of the plurality of laser devices is configured to emit electromagnetic radiation having a first wavelength different from the wavelength of a further laser device of the plurality of laser devices. A difference between the first wavelength and the wavelength of the further laser device is less than 20 nm.

A line field optical coherence tomography (OCT) system and an absorption spectrometer system employing a tunable or swept laser architecture. The laser is a cat's-eye configuration with a preferably transmissive tilt tuned interference thin film filter.