A vertical cavity surface emitting laser (VCSEL) including a substrate and a bottom distributed Bragg reflector (DBR) having a plurality of layers deposited on the substrate. The VCSEL also includes a first charge confining layer deposited on the bottom DBR, an active region deposited on the first charge confining layer, and a second charge confining layer deposited on the active region. A current blocking layer is provided on the second charge confining layer, and a top epitaxial DBR including a plurality of top epitaxial DBR layers is deposited on the current blocking layer. A top electrode is deposited on the top epitaxial DBR, a bottom electrode is deposited on the bottom DBR and adjacent to the active region, and a top dielectric DBR is deposited on the top epitaxial DBR and the top electrode.

A quantum cascade laser includes a semiconductor substrate, an optical waveguide formed on a first surface of the semiconductor substrate, and a temperature adjusting member. The optical waveguide includes a first region and a second region located on one side with respect to the first region in the optical waveguide direction of the optical waveguide. The first region generates a first light having a first wavelength, and the second region generates a second light having a second wavelength. The optical waveguide generates an output light having a frequency corresponding to a difference between the first wavelength and the second wavelength by difference-frequency generation. A recess for suppressing heat transfer between the first region and the second region is formed at a second surface of the semiconductor substrate. The temperature adjusting member includes a first temperature adjusting member for adjusting the temperature of the second region.

The subject invention includes a semiconductor laser with the laser having a DBR mirror on a substrate, a quantum well on the DBR mirror, and an interior CGH with a back propagated output for emitting a large sized Gaussian and encircling high energy. The DBR mirror has a plurality of GaAs/AlGaAs layers, while the quantum well is composed of AlGaAs/InGaAs. The CGH is composed of AlGaAs.

A vertical cavity surface emitting laser includes a semi-insulating substrate having a major surface including a first area and a second area, an n-type semiconductor layer that is provided on the first area and unprovided on the second area, a semiconductor laminate that is provided on the n-type semiconductor layer, a cathode electrode that is connected to the n-type semiconductor layer, an anode electrode that is connected to a top surface of the semiconductor laminate, and a first conductor that is connected to the anode electrode and extends from the first area to the second area. The semiconductor laminate includes a first distributed Bragg reflector provided on the n-type semiconductor layer, an active layer provided on the first distributed Bragg reflector, and a second distributed Bragg reflector provided on the active layer. The first conductor includes an anode electrode pad provided on the second area.

A semiconductor device according to the present application includes a semiconductor substrate, an n-type first cladding layer provided on the semiconductor substrate, an n-type second cladding layer provided on the first cladding layer, an active layer provided on the second cladding layer, a p-type third cladding layer provided on the active layer, a surface electrode provided above the third cladding layer, a back surface electrode provided below the semiconductor substrate and a p-type diffusion prevention layer provided between the first cladding layer and the second cladding layer.

A control circuit in this laser equipment drives a drive circuit of a photonic crystal laser element under a predetermined condition. It was found that a wavelength width of a laser beam to be output from the photonic crystal laser element is dependent on a standardized drive current k and a pulse width T, and had a predetermined relationship with these. By meeting this condition, a laser beam with a plurality of wavelengths can be controlled and output.

A surface light-emission type semiconductor light-emitting device includes a first semiconductor layer; a light-emitting layer provided on the first semiconductor layer; a second semiconductor layer provided on the light-emitting layer; an uneven structure provided on the second semiconductor layer, the uneven structure including a protrusion and a recess next to the protrusion; a first metal layer covering the uneven structure; and a second metal layer provided between the uneven structure and the first metal layer. The second metal layer is provided on one of a bottom surface of the recess, an upper surface of the protrusion, or a side surface of the protrusion. The second metal layer has a reflectance for light radiated from the light-emitting layer, which is less than a reflectance of the first metal layer for the light.

Single-mode distributed-feedback (DFB) lasers including single mode DFB waveguides with tapered grating structures are provided herein. Tapered grating structures provide for single mode DFB waveguides with predictable single mode operation. Uniform grating structures may provide for single mode operation, however DFB waveguides implementing uniform grating structures may operate at one of two single modes. Advantageously, DFB waveguides with tapered gratings operate with a spectrally narrow single mode at the same predictable single mode for all DFB waveguides with substantially identical specifications. Such predictability may lead to increased yield during manufacture of DFB waveguides with tapered gratings.

For epitaxial-side-down bonding of quantum cascade lasers (QCLs), it is important to optimize the heat transfer between the QCL chip and the heat sink to which the chip is mounted. This is achieved by using a heatsink with high thermal conductivity and by minimizing the thermal resistance between the laser active region and said heatsink. In the epi-down configuration concerned, the active region of the QCL is located only a few micrometers away from the heatsink, which is preferable from a thermal standpoint. However, this design is challenging to implement and often results in a low fabrication yield if no special precautions are taken. Since the active region is very close to the heatsink, solder material may ooze out on the sides of the chip during the bonding process and may short-circuits the device, rendering it unusable. To avoid this happening, the invention proposes to provide a trench all around the chip with the exception of the two waveguide facets, i.e. the ends of the active region. This trench may be etched into the otherwise standard QCL chip or otherwise machined into the chip, providing an initially empty space for the volume of solder displaced by the chip during the epi-down bonding process, which empty space is occupied by the surplus solder without contacting the side of the chip and thus short-circuiting the device.

An encoder includes an optical scale that is so provided as to be pivotable around a pivotal axis and includes a polarizing portion having a polarization characteristic, a light outputting portion that outputs linearly polarized light toward the polarizing portion, and a light detecting portion that detects the linearly polarized light from the optical scale. The light outputting portion includes a vertical cavity surface emitting laser, and light emitted from the vertical cavity surface emitting laser spreads at an angle greater than or equal to 5° but smaller than or equal to 20°.