Sumitomo Electric Industries, Limited

Michio Murata

Jun-ichi Hashimoto

Takashi Kato

Ichiro Yoshida

Takeyoshi Masuda

Hiromi Nakanishi

Hiroshi Inada

Masayuki Shigematsu

Tsukuru Katsuyama

Mitsuaki Nishie

Tomokazu Katsuyama

Nobuyuki Ikoma

Atsushi Hamakawa

Jiro Fukui

Hidetoshi Kobayashi

A quantum cascade laser includes a semiconductor substrate including a principal surface; a mesa waveguide disposed on the principal surface of the semiconductor substrate, the mesa waveguide including a light emitting region and an upper cladding layer disposed on the light emitting region, the mesa waveguide extending in a direction orthogonal to a reference direction; and a current blocking layer formed on a side surface of the mesa waveguide. The light emitting region includes a plurality of core regions and a plurality of buried regions. The core regions and the buried regions are alternately arranged in the reference direction. The core region at a central portion of the mesa waveguide has a width smaller than a width of the core region at a peripheral portion of the mesa waveguide in the reference direction.

Quantum cascade laser

A quantum cascade laser includes a semiconductor substrate including a principal surface; a mesa waveguide disposed on the principal surface of the semiconductor substrate, the mesa waveguide including a light emitting region and an upper cladding layer disposed on the light emitting region, the mesa waveguide extending in a direction orthogonal to a reference direction; and a current blocking layer formed on a side surface of the mesa waveguide. The light emitting region includes a plurality of core regions and a plurality of buried regions. The core regions and the buried regions are alternately arranged in the reference direction. The core region at a central portion of the mesa waveguide has a width larger than a width of the core region at a peripheral portion of the mesa waveguide in the reference direction.

An optical assembly is disclosed where the optical assembly provides an optical device and a holder including a sleeve, a skirt, and a lens. The sleeve has a bore, into which an external optical fiber is set to couple with the optical device, providing a target surface in an end thereof. The target surface includes an aiming index to indicate the axis of the lens.

Optical assembly and method for producing the same

A quantum cascade semiconductor laser includes a n-type semiconductor substrate, the substrate having a main surface; a mesa waveguide disposed on the substrate, the mesa waveguide including a core layer and an n-type upper cladding layer disposed on the core layer; a first semiconductor layer disposed on a side surface of the mesa waveguide and the main surface of the substrate, the first semiconductor layer being in contact with the side surface of the mesa waveguide; and a second semiconductor layer disposed on the first semiconductor layer. The first semiconductor layer and the second semiconductor layer constitute a burying region embedding the side surfaces of the mesa waveguide. The first semiconductor layer is formed of at least one of a semi-insulating semiconductor and a p-type semiconductor. In addition, the second semiconductor layer is formed of an n-type semiconductor.

Quantum cascade semiconductor laser

A semiconductor optical modulator with the Mach-Zender type is disclosed. The optical modulator of the invention cab driven by a single phase signal and reduce the chirping of the modulated light. Two waveguides of the Mach-Zender modulator each including an active layer showing the exciton resonance in the refractive index are connected with a resistor. The driving signal is applied to one of the waveguides, while, the signal is applied to the other waveguide through the resistor where the other waveguide is grounded through a resistor. Adjusting the resistance of two resistors and the amplitude of the applied signal, the Mach-Zender modulator shows a substantial modulation degree with substantially no chirping characteristic.

Optical modulator having Mach-Zender arrangement and method to generate modulated optical signal using the same

A semiconductor diffraction grating device includes a semiconductor substrate having a principal surface, a semiconductor core layer and a semiconductor cladding layer provided on the principal surface, and a chirped grating structure provided between the semiconductor core layer and the semiconductor cladding layer. The chirped grating structure includes a first region, a second region, and a third region arranged in that order in a predetermined axis direction, the first, second, and third regions including a plurality of projections constituting a chirped grating. The plurality of projections are provided at placement positions arranged with a predetermined pitch in the predetermined axis direction. The coupling coefficient &#x3ba; of the chirped grating monotonically increases in the predetermined axis direction to a predetermined value in the first region, remains flat in the second region, and monotonically decreases in the predetermined axis direction from the predetermined value in the third region.

Semiconductor diffraction grating device and semiconductor laser

In an integrated semiconductor optical device, a first cladding layer is made of a first conductivity type semiconductor. A first active layer for forming a first semiconductor optical device is provided on the first cladding layer in a first area of a principal surface of a substrate. A second active layer for forming a second semiconductor optical device is provided on the first cladding layer in a second area of the principal surface. A second cladding layer made of a second conductivity type semiconductor is provided on the second active layer. A third cladding layer made of a first conductivity type semiconductor is provided on the first active layer. A tunnel junction region is provided between the first active layer and the third cladding layer. The first active layer is coupled to the second active layer by butt joint. The second and third cladding layers form a p-n junction.

Integrated semiconductor optical device and optical apparatus using the same

A semiconductor optical device where the leak current due to the double injection of carriers may be suppressed and a simplified process to form the device are disclosed. The deviceprovides, on the n-type InP substrate, a mesa and a burying region formed so as to bury the mesa. The mesa includes the first cladding layer, the active layer, the tunnel junction layer and the second cladding layer on the n-type InP substrate in this order. The tunnel junction layer comprises an n-type layer coming in contact with the active layer and a p-type layer between the active layer and the n-type layer. The n-type layer has a carrier concentration higher than that of the second cladding layer, while, the p-type layer may have the band gap energy greater than that of the second cladding layer.

Semiconductor optical device with suppressed double injection phenomenon

The present invention is to provide a light-emitting device, a laser diode, formed without using the mechanical cleavage, and a process for manufacturing the device. The process comprises, after stacking semiconductor layers of the first cladding layer, the active layer, and the second cladding layer, a forming of a groove to define the laser resonator, the depth of which reaches the substrate, and the mass-transportation, within the groove, from the side surface of the groove in a portion of the substrate and the first cladding layer to the facet of the active layer and the second cladding layer. Since the facet layer thus transported reflects the crystal orientation of the side of the groove, the crystal quality of the facet layer can be maintained.

Semiconductor light-emitting device and a method for manufacturing the same

The present invention provides a structure of a light-emitting device which prevents the inter diffusion of impurities from the high-doped n-type InP substrate to a p-type current blocking layer. The substrate of the invention is highly doped with sulfur (S) to obtain high quality surface whose etch pit density (EPD) is less than 100 cm. The device includes such substrate, an optical guiding portion with an active layer, and a current blocking portion provided so as to bury the guiding portion. This current blocking portion includes, from the side of the substrate, a p-type layer, an n-type layer and another p-type layer. The device of the invention provides an n-type layer that is moderately doped with silicon between the n-type substrate and the p-type current blocking layer to prevent the inter diffusion of impurities from the substrate to the p-type layer.

Light-emitting device on n-type InP substrate heavily doped with sulfur

The present invention provides a semiconductor optical devicethat includes a photodiode capable of monitoring front light of the light-emitting device. The optical deviceincludes a photodiode, which is formed on a substrateand has an absorption layerand a semiconductor layer, and an optical waveguidealso formed on the substrate. The optical waveguideincludes, in addition to the active layer, two semiconductor layersand. A portion of the light from the active layerenters the photodiodereflected by the end surfaceof the waveguideand the rest portion of the light passes through the end surfaceand outputs therefrom. In the present invention, the photodiodeand the waveguideare integrally formed on the substrate

Semiconductor optical device integrated with a photo detector

A semiconductor optical integrated devicecomprises a light-emitting element portion, modulation element portion, and separation portionon a substrate. Light-emitting element portioncomprises a semiconductor laser element portion, and modulation element portioncomprises a modulation element portion. Separation portionis formed between light-emitting element portionand modulation element portion. In separation portion, a semiconductor embedded portionis provided in a second clad layer. Whereas second clad layerconsists of p-type InP, semiconductor embedded portionconsists of n-type InP. Hence semiconductor embedded portionhas the effect of impeding the leakage current flowing between electrodesand. As a result, the leakage current occurring between electrodesandvia second clad layeris reduced.

Semiconductor optical integrated device having a light emitting portion, a modulation section and a separation portion

In the present method, at the time when a semiconductor laser is being made, nitrogen or phosphorus element is introduced into an active layer comprising a GaAs based compound from an end face thereof, thereby changing the region of the active layer in the vicinity of the end face into a GaN or GaP based compound. Accordingly, the energy band gap of this region is made wider than the energy band gap within the active layer, and thus substituted region is changed into a layer transparent to the laser light generated within the active layer. Thus, the end face can be prevented from deteriorating upon the temperature rise caused by laser light absorption at the end face.

Semiconductor laser and method of making the same

The present invention relates to a light emitting device module which can easily be made and can yield a stable output characteristic, and a method of making the same. The light emitting device module in according to the present invention comprises a semiconductor device in which an active region having a light exit facet and a light reflecting facet with a lower light reflectivity than the light exit facet respectively at both ends is fabricated along a predetermined reference axis, and an optical fiber having a grating provided along the longitudinal direction of the core region and an end facet arranged so as to face the light exit facet. In particular, in the light emitting device module according to the present invention, the light exit facet of the active region is inclined with respect to the light reflecting facet of the active region by a predetermined angle, thereby the light reflecting facet of the active region and the grating constitute an external cavity through the light exit facet.

Light emitting device module

A semiconductor laser diode which can be applied to optical fiber amplifiers to attain a high reliability and can generate light having a wavelength of about 1 .mu.m is provided. This semiconductor laser diode is formed on a GaAs substrate and has an active layer comprising a GaInAsP strained quantum well whose energy band gap is smaller than that of GaAs. Barrier layers each comprising GaInAsP whose band gap is greater than that of the active layer are bonded to the active layer through heterojunction. According to this structure, when the active layer and the barrier layers are grown, the amounts of supply of a Ga material and an In material can be controlled in a simple manner and a semiconductor laser diode having a high reliability can be realized.

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Yokohama, Japan

Michio Murata