An optical path cover is located on an optical path through which beam light travels. The optical path cover includes a cylindrical portion through which the beam light is capable of passing. A plurality of protruding portions are formed on inner walls of the cylindrical portion, the inner walls facing toward a side of an optical axis of the beam light. The protruding portions, each of which has a convex shape in cross-section taken perpendicularly to the optical axis, are arranged next to each other with the convex shape facing toward the side of the optical axis. Each of the protruding portions has an elongated shape extending along the optical axis.

An optical path cover is located on an optical path through which beam light travels. The optical path cover includes a cylindrical portion through which the beam light is capable of passing. A plurality of protruding portions are formed on inner walls of the cylindrical portion, the inner walls facing toward a side of an optical axis of the beam light. The protruding portions, each of which has a convex shape in cross-section taken perpendicularly to the optical axis, are arranged next to each other with the convex shape facing toward the side of the optical axis. Each of the protruding portions has an elongated shape extending along the optical axis.

An optical transmitter module includes a semiconductor laser device, optical modulator, temperature adjusting device which includes a substrate, a first installation part and a second installation part, a package having a bottom surface opposite to a back surface of the substrate, the package housing the semiconductor laser device, the optical modulator, and the temperature adjusting device; and a middle block disposed between a first temperature controlling element a the second temperature controlling element, the middle block having a back surface directly or indirectly fastened to a principal surface of the substrate.

A light source apparatus for endoscope includes a light source, a collective lens, a light shielding member which shields at least a part of the light emitted from the light source, and allows light which is not shielded, to be transmitted as transmitted light, an optical fiber on which, the transmitted light transmitted through the light shielding member is incident, a holding member which includes a heat insulating member, and holds at least one of the light source, the collective lens, and the light shielding member by fixing at a respective position thereof, and a heat exhausting member which exhausts heat generated in the light shielding member to an outside of the holding member.

Methods and systems for reducing SWaP in combinations of laser diode drivers (LDDs) and diode laser pump modules (DPMs) are disclosed.

A tunable laser has a solid state laser medium with optical gain region and generates coherent radiation through a facet. A lens collects the coherent radiation and generates a collimated light beam. An external cavity includes a reflective surface and an optical filter, the reflective surface reflecting the collimated beam back to the lens and laser medium, the optical filter positioned between the reflective surface and the lens and having two surfaces and a thermally tunable optical transmission band within the optical gain region of the laser medium. The optical filter (1) transmits a predominant portion of the collimated beam at a desired wavelength of operation, and (2) specularly reflects a remaining portion of the collimated beam from each surface, the collimated beam being incident on the optical filter such that the reflected collimated beams propagate at a non-zero angle with respect to the incident collimated beam.

The optical module includes: a housing having first and second end walls and a pair of side walls; a semiconductor laser element; a first TEC; a wavelength locker unit including an optical splitting component and an etalon filter; and a second TEC. The second end wall is provided with a feedthrough. The pair of side walls is not provided with an external connection terminal. The second TEC is disposed between the first TEC and the second end wall and has: a first substrate thermally coupled to a bottom surface of the housing; a second substrate thermally coupled to the etalon filter; and a heat transfer part that transfers heat. The optical module further includes a wiring pattern that is arranged side by side with the heat transfer part and that supplies electric power to the first TEC from the feedthrough.

The present invention relates to a semiconductor laser device capable of reducing a measurement error of a temperature detecting element for detecting the temperature of a semiconductor laser element and accurately controlling the temperature of the semiconductor laser element. The semiconductor laser device is used for optical analysis and includes: a semiconductor laser element; a temperature detecting element that detects the temperature of the semiconductor laser element; output terminals that output the output of the temperature detecting element to the outside; wires that electrically connect the temperature detecting element and the output terminals; and a heat capacity increasing part that is provided interposed between the temperature detecting element and output terminal, and the output terminal, and contacts with at least part of the wires to increase the heat capacity of the wires.

An atomic oscillator includes a semiconductor laser, an atomic cell, a light receiving element, a first temperature control element, and a second temperature control element. The semiconductor laser includes a first mirror layer, a second mirror layer, and an active layer disposed between the first mirror layer, the second mirror layer, and a heat transfer member disposed on the second mirror layer. The atomic cell is irradiated with light emitted from the semiconductor laser. In the atomic cell, an alkali metal atom is accommodated. The light receiving element detects intensity of light transmitted through the atomic cell and outputs a detection signal. The first temperature control element controls a temperature of the semiconductor laser. The second temperature control element is controlled based on the detection signal and is connected to the heat transfer member.

Provided is a laser system that includes a laser head having a laser holder configured to house a laser beam and a lens for reflecting the laser beam at a predetermined wavelength, and a thermal-mechanical adjustment device disposed on the laser head and configured to adjust a temperature and an alignment of the laser beam, to maintain the predetermined wavelength of the laser beam.