In some implementations, an optical device may include a base with a first coefficient of thermal expansion (CTE). The optical device may include an opto-mechanical component with a second CTE attached to a surface of the base via a solder layer. The first CTE and the second CTE may differ by greater than a threshold amount. A spacer may be disposed within the solder layer to attach the opto-mechanical component to the base.

A diode laser bar assembly is formed to exhibit a relatively low thermal resistance, which also providing an increased range of conditions over which the internal stress conditions may be managed. In particular, the submount configuration of the prior art is replaced by a pair of platelets, disposed above and below the diode laser bar so as to form a sandwich structure. The bottom platelet is disposed between the heatsink (cooler) and the diode laser bar. Thus, the bottom platelet may be relatively thin, creating a low thermal resistance configuration. The combination of the top and bottom platelets provides the ability to create various configurations and designs that best accommodate stress conditions for a particular situation.

A semiconductor device according to the present disclosure includes an electrically conductive first electrode block, an electrically conductive submount, an insulating layer, a semiconductor element, an electrically conductive bump, and an electrically conductive second electrode block. The submount is provided in a first region of the upper surface of the first electrode block, and electrically connected to the first electrode block. The semiconductor element is provided on the submount, and has a first electrode electrically connected to the submount. The bump is provided on the upper surface of a second electrode, opposite the first electrode, of the semiconductor element, and electrically connected to the second electrode. A third region of the lower surface of the second electrode block is electrically connected to the bump via an electrically conductive metal layer. An electrically conductive metal sheet is provided between the metal layer and the bump.

Provided is a laser light source device which has a plurality of semiconductor laser elements arranged in an array and is provided with: a heat sink; a sub-mount substrate which is placed on one end edge of the heat sink, which has a power feed path, and on which the semiconductor laser array is mounted; an insulation plate placed in an area other than the sub-mount substrate on the heat sink; a first electrode plate mounted on the insulation plate; a second electrode plate mounted on the insulation plate separately from the first electrode plate; metal wires electrically connecting respectively between the first electrode plate and the sub-mount substrate and between the second electrode plate and the semiconductor laser array; and a cooling block on which the heat sink is mounted and which has a cooling water flow channel inside of the cooling block.

A semiconductor laser device (1) includes a heat sink (20), a submount (30), a first electrode (60), an insulating layer (70), a semiconductor laser element (40), a connecting portion (50), and a second electrode (61). The submount (30) is conductive and on a first region (R1) of the upper surface of the heat sink (20). The first electrode (60) is conductive and on a second region (R2), different from the first region (R1), of the upper surface of the heat sink (20). The first electrode (60) is electrically connected either to at least part of a side surface of the submount (30) or to the upper surface of the submount (30).

A light emitting apparatus includes: a submount including a mounting face and an end face, and the end face having an upper edge apart from a front edge of the mounting face; and a quantum cascade laser disposed on the front edge and the mounting face. The quantum cascade laser includes: a laser structure having first, and second faces; a first electrode on the first face; a second electrode on the second face; and a reflecting structure on a first end face of the laser structure. The reflecting structure includes an insulating film having a first end on the first face and a second end on the second face, and a metal film having a first end on the first face, and a second end on the second face. The insulating film is disposed between the laser structure and the first end and the second end of the metal film.

A coaxial transmitter optical subassembly (TOSA) including a side-by-side laser diode and monitor photodiode package, consistent with embodiments of the present disclosure, may be used in an optical transceiver for transmitting an optical signal at a channel wavelength. In an embodiment, the coaxial TOSA includes a laser sub-mount coupled to a mounting region defined by a body of the coaxial TOSA. The laser sub-mount includes a monitor photodiode disposed adjacent to a side of a laser diode such that a sensor region of the monitor photodiode is disposed within, or in close proximity to, a light cone emitted by a light emitting surface of the laser diode. The monitor photodiode is thus configured to directly receive a portion of emitted channel wavelengths from the laser diode for monitoring purposes.

Apparatus include a conductive block including a base surface and a plurality of parallel stepped surfaces opposite the base surface and defining respective mounting surfaces situated to receive respective laser diodes having respective thermal paths defining a common thermal path distance from the mounting surfaces to the base surface, and a two-phase cooling unit including a coupling surface attached to the base surface of the conductive block and wherein the two-phase cooling unit is situated to conduct heat generated through the emission of laser beams from the laser diodes along the thermal paths.

To provide an optical subassembly, an optical module, and an optical transmission equipment including simpler components. A first component with an optical semiconductor device mounted thereon that dissipates heat generated by the optical semiconductor device to outside, a second component in contact with the first component to form a box type housing, and a receptacle terminal that optically joined to the optical semiconductor device are provided, wherein the second component includes a window structure for transmitting light transmitted between the optical semiconductor device and the receptacle terminal, and the receptacle terminal is fused and fixed to the outside of the window structure.

A configuration of a DFB laser-based wavelength tunable laser is well known, but long resonators have difficulty in forming uniform resonators due to production variations, thereby inducing limitation in narrowing the spectral linewidth in the DFB laser-based wavelength tunable laser as well. In the semiconductor laser device of the present invention, a semiconductor laser that oscillates in a single mode and a low-loss lightwave circuit using SiO.sub.2 glass are arranged on the common substrate. The lightwave circuit is configured such that part of output light from the semiconductor laser propagates through a certain length of an optical path, and then is reflected by a reflector and is fed back to the semiconductor laser. Output light from the semiconductor laser and an input waveguide of the lightwave circuit can also be configured to be optically connected directly to each other. The present invention can provide a compact laser device with a narrowed spectral linewidth and stable wavelength controllability.