A light source module includes a first semiconductor laser element hermetically sealed, a second semiconductor laser element hermetically sealed, and firth to fourth optical elements. A first laser beam prior to reaching the first optical element has divergence angle θfd1 in a direction along a second optical axis and divergence angle θsd1 in a direction along a third optical axis, and satisfy 90°>θfd1>θsd1>0°. Divergence angle θfd12 of a first laser beam in the direction along the second optical axis decreases from divergence angle θfd1, the first laser beam having exited the first optical element. A component of a first laser beam in the direction along the second optical axis is collimated, the first laser beam having exited the second optical element. The same applies to the second semiconductor laser element.

Exemplary methods and apparatus may provide optical gates and optical switches using such optical gates. Each optical gate may include a semiconductor optical amplifier that is placed in a substrate. The semiconductor optical amplifier may be coupled to input and output couplers to receive and selectively output optical signals into and out of the substrate.

Exemplary methods and apparatus may provide optical gates and optical switches using such optical gates. Each optical gate may include a semiconductor optical amplifier that is placed in a substrate. The semiconductor optical amplifier may be coupled to input and output couplers to receive and selectively output optical signals into and out of the substrate.

A light emitting device includes: at least one semiconductor laser element; and a light-transmissive member including: an upper surface, a lower surface, and a light-transmissive region through which laser light emitted from the at least one semiconductor laser element is transmitted from the lower surface to the upper surface, wherein: at least the light-transmissive region is made of sapphire, the light-transmissive member includes an incident surface on which the laser light is incident, the incident surface being an a-plane of the sapphire, and the light-transmissive member is oriented such that a polarization direction of the laser light incident on the incident surface is parallel or perpendicular to a c-axis of the sapphire in a top view.

A laser package is described, the laser package comprising a plurality of laser diodes separately attached to at least one sub-mount having respective connecting pads, wherein, during operation, each of the laser diodes emits light having a fast axis and a slow axis defining a fast axis plane and a slow axis plane, wherein the fast axis planes of all laser diodes are parallel to each other and the distance between the fast axis planes of at least two laser diodes is smaller than the lateral distance between these laser diodes. Furthermore, a system with at least two laser packages is described.

Implementing systems and methods for operating a LiDAR system. The methods comprise: supplying current from a laser diode bar driver of the LiDAR system to a light source of the LiDAR system; passing the current through a laser diode bar of the light source (the laser diode bar comprising a plurality of laser diodes electrically connected in series); emitting a light beam from the light source when current is passing through the plurality of laser diodes; and/or receiving light reflected off an object.

A light emitting device includes first and second semiconductor laser elements, a base, a surrounding part, a wavelength converting member, and first and second wiring parts. The first laser element, the converting member and the second laser element are arranged in order in a first direction. At least one of the first and second laser elements is disposed between the first and second wiring parts in a second direction perpendicular to the first direction. An outermost periphery of the converting member is between a first imaginary line and a second imaginary line in the top view. The first and second imaginary lines are both parallel to the second direction. The first imaginary line passes through an outermost periphery in the first direction of the second laser element and the second imaginary line passes through an outermost periphery in a direction opposite to the first direction of the first laser element.

A light emitting device includes first and second semiconductor laser elements, a base, a surrounding part, a wavelength converting member, and first and second wiring parts. The first laser element, the converting member and the second laser element are arranged in order in a first direction. At least one of the first and second laser elements is disposed between the first and second wiring parts in a second direction perpendicular to the first direction. An outermost periphery of the converting member is between a first imaginary line and a second imaginary line in the top view. The first and second imaginary lines are both parallel to the second direction. The first imaginary line passes through an outermost periphery in the first direction of the second laser element and the second imaginary line passes through an outermost periphery in a direction opposite to the first direction of the first laser element.

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 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.