Mitsubishi Denki Kabushiki Kaisha

Masatoshi Fujiwara

Syoichi Kakimoto

Akira Takemoto

Yuji Ohkura

Hitoshi Watanabe

Syogo Takahashi

A semiconductor device with an improved speed response has a linear ridge pattern including an active layer, a cladding layer, a current blocking layer, and a contact layer on a semiconductor substrate. The insulating layer may be formed in a pattern having a high resistance to dry etching along a longitudinal side of the ridge pattern.

Method of manufacturing semiconductor devices separated from a wafer

A single wavelength oscillating semiconductor laser device having at least two diffraction gratings in an active region in which the order of a first diffraction grating disposed in the center of the laser is higher than that of a second diffraction grating disposed in the neighborhood of resonator facets.

Semiconductor laser including periodic structures with different periods

A method for manufacturing a diffraction grating includes applying a resist, the developing speed of which has an extreme at a certain exposure intensity, to a substrate on which the diffraction grating is to be formed, performing interference exposure of the resist with maximum and minimum values of exposure intensity respectively larger and smaller than the intensity which makes the developing speed an extreme, developing the resist, and etching the substrate using the remaining resist as a mask.

Method of manufacturing a diffraction grating for a semiconductor laser

A method of producing a .lambda./4 shifted diffraction grating, includes applying an image reversible resist on a substrate on which a diffraction grating is to be formed, exposing a predetermined with light of a first predetermined region of the resist with light of a first predetermined energy, exposing all of the resist with light interference fringes of a second predetermined energy, baking, and thereafter developing the image reversible resist.

Method of producing a .lambda./4-shifted diffraction grating

A semiconductor laser device having an active layer sandwiched by semiconductor layers having larger energy band gaps than that of the active layer, includes a semiconductor absorption layer having an energy band gap no larger than that of the active layer and having a thickness periodically changing in the cavity length direction of the resonator, close to the active layer so that light which is generated at the active layer reaches the absorption layer, and a semiconductor refractive index matching layer, having a larger energy band gap than that of the active layer and a higher refractive index than those of the semiconductor layers sandwiching the active layer, to make the equivalent refractive indices in layer thickness direction substantially equal along the resonator direction.

Method of producing a semiconductor laser

A semiconductor laser device having an active layer sandwiched by semiconductor layers having larger energy band gaps than that of the active layer, includes a semiconductor absorption layer having an energy band gap no larger than that of the active layer and having a thickness periodically changing in the cavity length direction of the resonator close to the active layer so that light which is generated at the active layer reaches the absorption layer, and a semiconductor refractive index matching layer having a larger energy band gap than that of the active layer and a higher refractive index than those of the semiconductor layers sandwiching the active layer to make the equivalent refractive indices in layer thickness direction substantially equal along the resonator direction.

Semiconductor laser device

A method for producing a .lambda./4 shift type diffraction grating by producing a diffraction grating pattern on a substrate with a material capable of being selectively etched relative to the substrate, depositing a resist to bury the diffraction grating pattern, removing a portion of the resist to expose at least a portion of the surface of the diffraction grating pattern, removing the diffraction grating pattern on a first portion of the substrate, etching the first portion of the substrate using the remaining resist pattern as a mask, and etching a second portion of the substrate adjacent to the first portion using the remaining diffraction grating pattern on the second portion of the substrate, thereby producing a .lambda./4 shift type diffraction grating having a .lambda./4 phase shift region at the junction of the first and second portions of the substrate.

Method for producing a .lambda./4 shift type diffraction grating

A distributed feedback semiconductor laser which achieves a phase shift for stabilizing the longitudinal mode without a substantial increase in reactive current and without introducing dimensional discontinuities in the laser stripe. The active layer of the laser is configured as a multi-quantum well and impurities are selectively diffused into the multi-quantum well to disorder a selected portion of the active layer. The disordered portion has an optical propagation constant which is different than that of the remaining stripe, and the difference in propagation constant coordinated with the length of the phase adjustment section produces a phase shift adequate to stabilize the laser longitudinal mode.

Semiconductor laser and method for production thereof

A method for producing a semiconductor laser comprising depositing a first semiconductor layer comprising n-type InP on an n-type InP substrate, depositing a diffraction grating of InGaAsP which includes or excludes doping impurities on the first semiconductor layer with irradiating interference fringes by a light excitation crystalline growth means, and burying a portion of the diffraction grating with InGaAsP including or excluding doping impurities with irradiating interference fringes reverse in light and darkness from said interference fringes used in depositing the diffraction grating.

Growing community of inventors

Itami, Japan

Masatoshi Fujiwara