Kabushiki Kaisha Toshiba

Harison Toshiba Lighting Corporation

Junichi Kinoshita

Kazuaki Otsuka

Takao Mizukami

Yuji Wagatsuma

Tsuneo Nakayama

Kiyoshi Matsunaga

Naoki Matsuoka

Norihiko Ochi

A light emitting device includes: a light emitting element; a substrate including a groove-like light guide extending along a first direction, emission light emitted from the light emitting element and introduced into the light guide being reflected by an inner wall surface of the light guide, spreading along the first direction, and being turned into upward light directed upward above the substrate; and a lens provided above the light guide and configured to collect the upward light and control light distribution characteristic in a plane generally perpendicular to the first direction.

Light emitting device and method for manufacturing same, lighting fixture, and lighting system

A package for light emitting element including a package main bodyhaving a bottom faceon which a light emitting elementis arranged, and a concave portionwhich is formed in an inverted truncated cone shape by an inner wall faceintersecting with the bottom facewith a predetermined angle, and a translucent memberfilled in the concave portionof the package main body, the angle between the inner wall facecomposing the concave portionand the bottom faceis selected within &#xb1;15&#xb0; of the incident critical angle in which a direct light radiated from the light emitting elementundergoes total reflection at the interface between the translucent memberand air.

Package for light emitting element and manufacturing method thereof

It is an object of this invention to overcome the problems of prior art by a unique arrangement based on a novel idea, and to provide an optical device having desired characteristics and an optical module and optical system incorporating the optical device. Provided is a photonic crystal including a three-dimensional periodic structure formed by using a first material which changes in properties relatively easily and a second material which does not change in properties relatively easily, wherein the first material is preferentially allowed to change in properties to make a refractive index difference between the first and second materials larger than that before the property change. Also provided is an optical device including a photonic waveguide, gain means, and reflecting means, wherein resonance is generated by reversing the propagating direction of light propagating in the photonic waveguide by the reflecting means while a gain is given to the light by the gain means.

Optical device and optical module

A surface emitting laser that provides an improved temperature characteristic, an improved optical output, and easy forming process. An optical communication system using this surface emitting laser is also provided. A surface emitting laser comprising: a substrate; a vertical cavity of layers formed on said substrate for propagating and resonating light along an axis vertical to a surface of said substrate, said light emitted from an active layer by current injection; and a reflective film disposed concentrically with the vertical axis around the outer periphery of said vertical cavity for reflecting the light from said active layer in a horizontal direction parallel to the surface of said substrate, the light emitted from said active layer forming a laser beam due to resonation, which laser beam is then emitted in a vertical direction. An optical communication system using the surface emitting laser.

Semiconductor laser diode and optical communication system

In order to realize an optical functional device like a DFB laser in which the radiation mode loss is small and the threshold current is low even when high-order gratings easy to process are used, the gratings are configured to be asymmetric in its cross-sectional structure. Then, by partly varying the asymmetry (blaze angle) of the cross-sectional structure of the gratings along the cavity lengthwise direction, the cavity-lengthwise profile of radiation modes from the high-order gratings is controlled. It is also controlled by using a relationship between a phase shift of the gratings and the asymmetry. In a edge emitting DFB laser, by utilizing destructive interference among radiation modes, the radiation mode loss is reduced, and the threshold can be decreased. When a radiation mode is used as an output, the radiation mode can be reinforced to increase the output by utilizing constructive interference.

Optical functional devices their manufacturing method and optical communication system

A medium having the function of light emission or optical amplification induced by optical pumping is surrounded by an annular laser (ring laser) having a diffraction grating (holographic structure) of the second order or more. The output of the ring laser emits through this diffraction grating (holographic structure) and is extracted as radiation mode. This is used as pumping light to be input to the medium that is disposed in the vicinity of the center of the assembly. To stabilize the threshold of the longitudinal mode, which has a greater amount of radiation mode, a gain medium and a reflective structure could be further provided around the periphery of this ring laser. This element also plays a role of optical pumping from the sides of a VCSEL.

Optical amplification and light emitting element

First and second thin-film layers having different compositions are inserted between cladding layers to be stepped, and steps corresponding to a difference between the side etching amounts of these layers are formed. In this manner, symmetrical steps of about 0.5 &mgr;m can be reliably and easily formed on the side surfaces of a ridge waveguide.

Waveguide optical device and method of fabricating the same

A distributed feedback laser comprising: waveguide (,) having a hologram (,) capable of emitting radiation mode light in upper and lower directions; first reflector (,) provided below said waveguide for returning said radiation mode light back to said waveguide; and second reflector (,A,,B,,C,,D,,E) provided above said waveguide for returning said radiation mode light back to said waveguide, intensity profile of said radiation mode light on said waveguide being non-uniform is disclosed. Also, by using 2nd- or higher-order diffraction gratings having an asymmetric cross-sectional configuration together with a reflection structure located at one side thereof, a highly directional optical isolator can be provided. Further, the present invention provides an optical functional element comprising: first waveguide which guides optical waves and has a grain or a loss, said waveguide having a hologram (,) capable of coupling with said optical waves guided by said waveguide to generate radiation mode light; amplifier (,) for amplifying said radiation mode light released from said first waveguide and releasing it; and first reflector (,) for reflecting said radiation mode light emitted from said amplifier back to said first waveguide.

Optical functional element and transmission device

Both an electric energy applying mechanism and an optical waveguide mechanism can be provided to an ITO layer (transparent electrode) by constituting an optical waveguide so as that the guided mode profile spread into the ITO layer. Also a bonding pad is provided to supply a power and apply an electric field onto the ITO layer. Accordingly, a device structure can be simplified and thus improvement in yield of the optoelectronic device having an optical waveguide and improvement in parameters of the optoelectronic device can be achieved.

Optoelectronic device and laser diode

In a guiding structure having a corrugation, depth of the corrugation is changed in the axial direction to change the effective refractive index by a considerable amount. The use of a 2nd-order or higher-order corrugation is desirable to ensure precise processing. It is also desirable that changes in depth is continuous. In a DFB laser using this structure, effective phase shifting and optical confinement factor can be controlled by changing the depth of the corrugation. In a DFB laser/modulator integrating device commonly using an active layer and an absorption layer, changes of the corrugation in the axial direction, including the presence or absence thereof, can considerably change optical confinement factor to the absorption layer and the active layer.

Optically functional device

A transmitter and a receiver for wavelength division multiplexing optical transmission need no multiplexer and can be made compact and manufactured easily while promising a high reliability of a system using them. By using second-order Bragg diffraction gratings to form the output mechanism, a plurality of DFB laser-type elements can be integrated so that their optical outputs adversely affect each other. Therefore, a plurality of lasers can be arranged coaxially to form a light source for wavelength division multiplexing optical transmission without using a multiplexer. By using the same mechanism on the part of a receiver, a demultiplexer can be omitted.

Wavelength division multiplexing optical transmission device and

A burying-heterostructure (BH) type semiconductor laser having a constricted mesa which has an active region. The laser has two spaces, located above and below the active region, for constricting a current to reduce a leakage current. The laser further has a first group of columns extending through the space located above the active region, and a second group of columns extending through the space located below the space. The columns of the first group are staggered in a vertical plane, with respect to the columns of the second group.

Semiconductor device having a current-constricting spaces and method of

Disclosed are a semiconductor light emitting element whose temperature characteristics are compensated for so as to provide a stable temperature characteristics in a temperature range from -40.degree. C. to +85.degree. C., and an optical fiber transmission system using the same semiconductor light emitting element. In the semiconductor light emitting element, an active layer (2) is buried on an n-type InP semiconductor substrate (1) formed with an n-side electrode (21). The upper layers (4, 5) are covered with an insulating film (22). A p-side electrode (20) is formed on the uppermost layer of the semiconductor substrate so as to cover the insulating film (22). A relatively large metallic resistance element (30) whose resistance increases with increasing temperature is wired on the insulating film (22) as a shunt path, so as to compensate for the temperature characteristics of the semiconductor light emitting element. Therefore, since leakage current is large at a low temperature, the threshold current is high, so that the slope efficiency is small. On the other hand, since leakage current is reduced at a high temperature, a rise in the threshold current and a drop of the slope efficiency can be both compensated for.

Semiconductor light emitting element and optical fiber transmission

A GCL is formed on a first major surface of a semi-insulating InP substrate. Specifically, an InGaAsP active layer, an InGaAsP waveguide path and a striped grating having two phase shift portions are formed on the first major surface of the InP substrate. An EA modulator is formed on a second major surface of the semi-insulating InP substrate. Specifically, a p-InP layer, an MQW structure of 100-layer, an n.sup.- -InP layer and an n.sup.+ -InP layer are formed on the second major surface of the InP substrate. The first major surface and second major surface of the InP substrate are inclined to each other by a few degrees.

Integrated device with monolithically formed light emitting element and

A linear active layer, a current block layer and a clad layer are formed on the first major surface of a wafer, while a first electrode is formed on the second major surface of the wafer. A linear first opening is formed in the first electrode. The wafer exposed to the first opening is etched to form a first guide groove linearly extending in a direction perpendicular to the active layer. A second electrode is formed on the clad layer and etched to form a linear second opening therein. The clad layer, current block layer and wafer, located directly under the second opening, are etched to form a second guide groove thereon so as to extend in a direction parallel to the active layer. The wafer is cleaved along the first guide groove to form bars each having semiconductor lasers. The bars are arranged in parallel to one another and separated from one another by the second guide groove. The wafer is cleaved or cut along the second guide groove to obtain semiconductor chips.

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Yokohama, Japan

Junichi Kinoshita