Abstract: Optical elements (light sources 16 or photodetectors 18) are arranged in a two-dimensional array, and the relative positional relationship between the optical elements and optical waveguides 12 is defined such that optical waveguides 12 extend between the optical elements in the two-dimensional array substantially parallel to substrate 19 for increased parallelism. Micromirrors 15 are disposed in respective optical waveguides 12 to bend light beams through 90 degrees to realize a highly efficient optical coupling between the optical elements and optical waveguides 12. The optical waveguides are stacked in multiple stages, and light beams are lead to the optical waveguides in the multiple stacks through micromirrors 15 across the stacked plane of the optical waveguides, thereby realizing parallel connection between the two-dimensional array of optical elements and a two-dimensional array of optical waveguides.

Abstract: Optical elements (light sources 16 or photodetectors 18) are arranged in a two-dimensional array, and the relative positional relationship between the optical elements and optical waveguides 12 is defined such that optical waveguides 12 extend between the optical elements in the two-dimensional array substantially parallel to substrate 19 for increased parallelism. Micromirrors 15 are disposed in respective optical waveguides 12 to bend light beams through 90 degrees to realize a highly efficient optical coupling between the optical elements and optical waveguides 12. The optical waveguides are stacked in multiple stages, and light beams are lead to the optical waveguides in the multiple stacks through micromirrors 15 across the stacked plane of the optical waveguides, thereby realizing parallel connection between the two-dimensional array of optical elements and a two-dimensional array of optical waveguides.

Abstract: Photodetectors 2a capable of converting optical signals that are received as input from the outside to electrical signals and supplying these electrical signals as output to output ports are mounted on two or more input ports of substrate 1 on which a semiconductor integrated circuit can be mounted; and moreover, the heights of these two or more photodetectors 2a are uniformly aligned, and the electrical signal input ports of the semiconductor integrated circuit that is mounted can be connected to the output ports of the above-described substrate 1.

Abstract: Light-emitting device array 2 is mounted on LSI 1, following which necessary light-emitting devices 2a among two or more light-emitting devices 2 that make up mounted light-emitting device array 2 are allowed to remain and unnecessary light-emitting devices 2a are removed in order to mount light-emitting devices on a plurality of output ports that are randomly arranged on LSI 1.

Abstract: An optical bistable device comprising a semiconductor laser including a diffraction grating which diffracts light parallel to the grating for laser resonance and additionally diffracts a higher order Bragg beam perpendicular to the grating. An optical detector receives the higher order beam and produces an electrical signal which is used as a partial exciting current for the semiconductor laser. Thereby, the two optical ports of the laser can be used for other purposes.

Abstract: A semiconductor laser for use as a bistable optical device in which an active semiconductor layer has corrugations of predetermined pitch on its surface and a semiconductor optical waveguide is formed on the corrugation. At least one end of the active layer is exposed at an oblique angle so that light in the active layer propagating along the direction of corrugation is reflected from the oblique face to a normal of the surface of the laser. Electrodes are provided above and below the active layer.

Abstract: A double-channel planar buried-heterostructure semiconductor laser diode (DC-PBH LD) has improved high frequency response characteristics due to lower p-n junction capacitance resulting from the interposition of a low carrier concentration blocking layer between p-n-p-n blocking layers of the DC-PBH LD structure.

Abstract: A buried heterostructure semiconductor laser diode with improved efficiency, CW operating temperature and output characteristic is comprised of a semiconductor substrate of a first conductivity type and includes successively at least a first cladding semiconductor layer of the first conductivity type, an active semiconductor layer, and a second cladding semiconductor layer of a second conductivity type. The active semiconductor layer has a narrower bandgap than those of the first and second cladding semiconductor layers. The multilayer double heterostructure has a stripe geometry with channels formed along both sides of the stripe and extending down to the first cladding layer. A current blocking layer is formed on the multilayer double heterostructure except for the top surface of the stripe geometry, in order to block a current flow therethrough.

Abstract: In an integrated optical semiconductor device wherein a stripe geometry laser diode is separated from a photodetector by an etched groove, the stripe region has a smaller width, such as 2 to 3 microns, than a carrier generating region of the photodetector. The stripe region is preferably rendered thicker than the carrier generating region, in which case the carrier generating region is more preferably made of a seimconductor material having a narrower band gap than the material of the stripe region. The stripe region may be defined by a buried mesa structure. Alternatively, the stripe region may be bounded transversely of a pair of heterojunctions therefor by a pair of channel-shaped regions of a semiconductor material having a wider bank gap than the material of the stripe region. In this event, the carrier generating region is divided into three parts by extensions of the channel-shaped regions.

Abstract: A buried heterostructure laser diode and method for making the same wherein an active layer is provided in a semiconductor region forming a mesa stripe, and, except for the top surface portion of the mesa stripe, the side surface portion of the mesa stripe and the remainder are covered by a current-blocking layer. Furthermore, a current-confining layer covers only this current-blocking layer, and a clad layer covers the current-blocking layer and the top surface portion of the mesa stripe.

Abstract: An integrated laser array is disclosed in which a plurality of semiconductor lasers are integrated on a semiconductor multi-layer crystal that includes an active layer in which the band gap energy varies in one direction. By means of this arrangement a plurality of semiconductor lasers, which differ in their respective oscillating wavelengths over a relatively broad range, can be formed on a common substrate.

Abstract: An optical multiplexer-demultiplexer consisting essentially of a light-focusing transmission body having a radially graded refractive index distribution and a reflection or transmission type diffraction grating. The transmission body is given an axial length approximately equal to an integral multiple of one quarter of the pitch of undulation of an off-axis input light beam as travelling through the transmission body while the diffraction grating is arranged on the axis of the transmission body at a distance approximately equal to an odd multiple of one quarter of the pitch of beam undulation from one end face of the transmission body which is normal to the axis. A composite light beam directed into the transmission body is dispersed by the diffraction grating into wavelength components, which are separately focused to be extracted as through respective optical fibers.

Abstract: A semiconductor laser device in which a part of the laser output is reflected from an external reflector and injected into the laser element with a delay that is less than the relaxation oscillation period of the laser pulse output.

Abstract: The invention contemplates an improved means for coupling plural optical fibers to a single optical fiber, whereby coupling losses may be held to relatively low magnitude. Each of the plural optical fibers is fitted to a first end of an elongate light-transmitting body having an elongate body axis about which the refractive index decreases approximately proportional to the square of the distance from the axis, and these bodies are grouped with their body axes is close and substantially parallel array. The opposite ends of the light-transmitting bodies all spaced from and face the end of the single optical fiber, with the optical axis of said single end aligned with the elongation of the group; and an optical lens is placed on the optical axis between the group and the single-fiber end, with the latter near the focal plane of the lens.

Abstract: A semiconductor laser device is disclosed in which an external light beam having a wavelength approximately the same as at least one of the wavelengths of the resonance axial mode for the modulation semiconductor laser to oscillate is injected into the optical resonator of the modulation semiconductor laser.