A package for at least one laser diode includes: leads configured to be electrically connected to the at least one laser diode; a base including a mounting surface on which the at least one laser diode is to be mounted and a lateral wall located around the mounting surface so as to surround the at least one laser diode, the lateral wall defining first through-holes and including a light-transmissive part configured to transmit a laser beam emitted from the at least one laser diode; and a lead holding member bonded to the lateral wall of the base and defining second through-holes. The leads are disposed through the first through-holes and the second through-holes. At least a central portion of each of the leads is made of copper.

A package for at least one laser diode includes: leads configured to be electrically connected to the at least one laser diode; a base including a mounting surface on which the at least one laser diode is to be mounted and a lateral wall located around the mounting surface so as to surround the at least one laser diode, the lateral wall defining first through-holes and including a light-transmissive part configured to transmit a laser beam emitted from the at least one laser diode; and a lead holding member bonded to the lateral wall of the base and defining second through-holes. The leads are disposed through the first through-holes and the second through-holes. At least a central portion of each of the leads is made of copper.

Packaged light emitter module can provide improved safety features to facilitate sensing the presence of moisture or a mechanical defect such as a crack in a transmissive cover (22) that may result in a safety hazard caused by the emitted light (24) if the defect or other situation is not addressed in a timely manner. Different electrically conductive structures, such as different electrically conductive traces (20, 22), allow monitoring and detection of mechanical defects to be decoupled from monitoring and detection of problems arising from the presence of moisture. The decoupling can allow the respective configuration for each of the electrically conductive structures to be optimized for detection of particular situations that may lead to a safety hazard.

A semiconductor laser is provided that includes a semiconductor layer sequence and electrical contact surfaces. The semiconductor layer sequence includes a waveguide with an active zone. Furthermore, the semiconductor layer sequence includes a first and a second cladding layer, between which the waveguide is located. At least one oblique facet is formed on the semiconductor layer sequence, which has an angle of 45° to a resonator axis with a tolerance of at most 10°. This facet forms a reflection surface towards the first cladding layer for laser radiation generated during operation. A maximum thickness of the first cladding layer is between 0.5 M/n and 10 M/n at least in a radiation passage region, wherein n is the average refractive index of the first cladding layer and M is the vacuum wavelength of maximum intensity of the laser radiation.

A quantum cascade laser device includes a QCL element; a lens; and a lens holder having a small-diameter hole, a large-diameter hole, and a counterbore surface. At least a part of a side surface of the lens is fixed to an inner surface of the large-diameter hole in a state where an edge portion of an incident surface of the lens is in contact with the counterbore surface. A central axis of the small-diameter hole is eccentric from that of the large-diameter hole. The side surface of the lens is positioned with respect to the inner surface of the large-diameter hole along a direction from the central axis of the large-diameter hole toward the central axis of the small-diameter hole. A central axis of the lens is disposed at a position closer to the central axis of the small-diameter hole than to the central axis of the large-diameter hole.

A light emission device includes: a base part; a semiconductor laser device disposed on the base part; a frame body fixed to the base part and provided around the semiconductor laser device; a lid bonded to an upper surface of the frame body; and a first electrical conduction member bonded to an outer surface of the base part or an outer surface of the frame body, the first electrical conduction member having a first conductive region and a second conductive region that are electrically connected to the semiconductor laser device. In a top plan view, the first electrical conduction member includes a first portion overlapping the frame body and a second portion not overlapping the frame body, the first conductive region being contained in the first portion, and the second conductive region being contained in the second portion.

A light emission device includes: a base part; a semiconductor laser device disposed on the base part; a frame body fixed to the base part and provided around the semiconductor laser device; a lid bonded to an upper surface of the frame body; and a first electrical conduction member bonded to an outer surface of the base part or an outer surface of the frame body, the first electrical conduction member having a first conductive region and a second conductive region that are electrically connected to the semiconductor laser device. In a top plan view, the first electrical conduction member includes a first portion overlapping the frame body and a second portion not overlapping the frame body, the first conductive region being contained in the first portion, and the second conductive region being contained in the second portion.

A light emitting device includes: a substrate including a main surface; a first projection positioned on the main surface, the first projection including an upper surface and first and second lateral surfaces, wherein the first lateral surface of the first projection comprises a first reflective part, and the second lateral surface of the first projection comprises a second reflective part; a first laser element configured to irradiate laser light to the first reflective part; a second laser element configured to irradiate laser light to the second reflective part; and a first optical member fixed to the upper surface of the first projection, wherein the first optical member comprises a first lens part positioned above the first reflective part, and a second lens part positioned above the second reflective part.

A light source device includes: first and second laser diodes; a reflector having: first and second reflecting faces configured to reflect a portion of light from the respective first and second laser diodes and to transmit a portion of the light from the respective first and second laser diodes, and first and second exit faces configured to allow the portions of the light transmitted through the respective first and second reflecting faces to exit; and a photodetector including: first and second light receiving element configured to receive light exiting the first and second exit faces, respectively. The reflector is configured such that the light transmitted through the first reflecting face is hindered from exiting the second exit face and the light transmitted through the second reflecting face is hindered from exiting the first exit face.

A light source device includes: first and second laser diodes; a reflector having: first and second reflecting faces configured to reflect a portion of light from the respective first and second laser diodes and to transmit a portion of the light from the respective first and second laser diodes, and first and second exit faces configured to allow the portions of the light transmitted through the respective first and second reflecting faces to exit; and a photodetector including: first and second light receiving element configured to receive light exiting the first and second exit faces, respectively. The reflector is configured such that the light transmitted through the first reflecting face is hindered from exiting the second exit face and the light transmitted through the second reflecting face is hindered from exiting the first exit face.