Abstract: A communication system includes: a plurality of mobile communication terminals; a server device; and a plurality of relay devices performing a relay between the plurality of mobile communication terminals and the server device. The mobile communication terminals include: a communication unit transmitting and receiving a long wave wirelessly, and a processing unit performing a predetermined process based on received information.

Abstract: A communication system includes: a plurality of mobile communication terminals; a server device; and a plurality of relay devices performing a relay between the plurality of mobile communication terminals and the server device. The mobile communication terminals include: a communication unit transmitting and receiving a long wave wirelessly, and a processing unit performing a predetermined process based on received information.

Abstract: A hybrid recording medium includes a read-only area in which a file is previously recorded, and a write area capable of updating and recording the file, characterized in that volume configuration information 21 and VTOC 22 about a file system are recorded in the write area is used in an information record apparatus.

Abstract: A DFB type semiconductor laser device including a laser substrate, a grating layer, an insulating layer and an electrode layer, which are laminated in the given order. The insulating layer includes a through groove or grooves extending to the grating layer in a direction in which a resonator of the laser device is formed, and the electrode layer contacts the grating layer and a clad layer.

Abstract: A semiconductor laser includes an active layer made of semiconductor; a ridge stripe having a cladding layer formed on the active layer and a contact layer formed on the cladding layer to protrude from the active layer; a pair of gratings each having a periodic structure in a longitudinal direction of the ridge stripe having a plurality of grooves each extending from side walls of the ridge stripe on flat portions in both sides of the ridge stripe; and absorbing layers covering the surfaces of the grooves of gratings to absorb excited light.

Abstract: There is provided a method of manufacturing a ridge type LC-DFB semiconductor laser in which a laser substrate having a cladding layer made of a material for a ridge stripe formed on an active layer made of semiconductor. A stripe mask is formed on the cladding layer to form two lateral flat portions from the cladding layer, by a selective wet etching, so as to form a ridge stripe protruding therefrom and having a flat top portion at which the stripe mask capped. A grating mask is formed on the two lateral flat portions, side walls of the ridge stripe and the stripe mask. The grating mask has a periodic structure in the direction in which the ridge stripe extends.

Abstract: A description is provided of a ridge-structure DFB semiconductor laser and a method of manufacturing the laser wherein an optical absorption loss by a metal electrode formed on a grating can be avoided. The DFB semiconductor laser includes: a ridge protruding from flat portions of a cladding layer which is formed on an active layer, the ridge includes a cladding layer and a contact layer sequentially formed on the active layer; a plurality of metal strips having a predetermined periodicity along a longitudinal direction of the ridge and extending from a surface of at least one of the flat portions to a top of the ridge; and an insulating layer formed on the plurality of metal strips at the top of the ridge.

Abstract: An optical transmitter and receiver module de-multiplexes a multi-wavelength optical signal into at least an optical signal of one wavelength band, and receives and transmits the signal. The module includes a first substrate, with a cleavage plane, for supporting input and output wave guides which intersect each other at a portion on the cleavage plane and extend from the portion of intersection at an equal angle with respect to normal at the portion on the cleavage plane. The module also includes an interference filter that is in contact with the cleavage plane on the portion of intersection of the input and output wave guides of the first substrate. Further, the module includes a second substrate, with a cleavage plane in contact with the interference filter, for supporting a transmit/receive wave guide having receiver and transmitter wave guides which extend from the vicinity of the portion of intersection and are separated from each other.

Abstract: An optical integrated device is used in an optical pickup device which irradiates a light onto an optical information storage medium and receives a reflected light reflected by the storage medium. The optical integrated device includes: a light wave coupling element for generating at least a guided light from the reflected light; an optical waveguide unit for propagating the guided light, the optical waveguide unit including a multiple optical waveguides and at least a clad layer formed between the optical waveguides; and a light receiving element for receiving the light from the optical waveguide unit.

Abstract: An optical transmitter and receiver module de-multiplexes a superimposed optical signal into which at least a first and second wavelength band are superimposed, and receives and transmits an optical signal of the first wavelength band. The module includes an input/output wave-guide having an outer end portion and inner end portion for inputting superimposed optical signals, a receiver portion for receiving optical signals of the first wavelength band, an output wave-guide having an outer end portion and inner end portion for outputting optical signals of the second wavelength band, and a transmitter portion for transmitting the optical signals of the first wavelength band.

Abstract: A method for producing a distributed feedback semiconductor laser element includes the steps of forming a laser substrate, forming a ridge by etching the laser substrate, and forming a flattening layer on the ridge. A grating is then formed on the flattening layer and the grating is further transferred to the laser substrate on which the ridge is formed. The flattening layer is removed and electrodes are then formed.

Abstract: A description is provided of a ridge-structure DFB semiconductor laser and a method of manufacturing the laser wherein an optical absorption loss by a metal electrode formed on a grating can be avoided. The DFB semiconductor laser includes: a ridge protruding from flat portions of a cladding layer which is formed on an active layer, the ridge includes a cladding layer and a contact layer sequentially formed on the active layer; a plurality of metal strips having a predetermined periodicity along a longitudinal direction of the ridge and extending from a surface of at least one of the flat portions to a top of the ridge; and an insulating layer formed on the plurality of metal strips at the top of the ridge.

Abstract: A description is provided of a ridge-structure DFB semiconductor laser and a method of manufacturing the laser wherein an optical absorption loss by a metal electrode formed on a grating can be avoided. The DFB semiconductor laser includes: a ridge protruding from flat portions of a cladding layer which is formed on an active layer, the ridge includes a cladding layer and a contact layer sequentially formed on the active layer; a plurality of metal strips having a predetermined periodicity along a longitudinal direction of the ridge and extending from a surface of at least one of the flat portions to a top of the ridge; and an insulating layer formed on the plurality of metal strips at the top of the ridge.

Abstract: A method for producing a semiconductor laser module is provided which enables simplifying the production process by eliminating the process of positioning the laser light emitting portion on the substrate, as well as enabling positioning an optical fiber on an appropriate position without aligning the optical fiber with the laser light emitting portion. A semiconductor laser module is fabricated through a process including a substrate preparation step for preparing a substrate including an active layer between cladding layers; a supporting groove portion formation step for forming a supporting groove portion to support an optical fiber on the substrate; and an electrode formation step for forming an electrode on a substrate surface of an opposing portion which faces the supporting groove portion.

Abstract: A hybrid recording medium includes a read-only area in which a file is previously recorded, and a write area capable of updating and recording the file, characterized in that volume configuration information 21 and VTOC 22 about a file system are recorded in the write area is used in an information record apparatus.

Abstract: There is provided a method of manufacturing a ridge type LC-DFB semiconductor laser in which a laser substrate having a cladding layer made of a material for a ridge stripe formed on an active layer made of semiconductor. A stripe mask is formed on the cladding layer to form two lateral flat portions from the cladding layer, by a selective wet etching, so as to form a ridge stripe protruding therefrom and having a flat top portion at which the stripe mask capped. A grating mask is formed on the two lateral flat portions, side walls of the ridge stripe and the stripe mask. The grating mask has a periodic structure in the direction in which the ridge stripe extends.

Abstract: A method for producing a distributed feedback semiconductor laser element includes the steps of forming a laser substrate, forming a ridge by etching the laser substrate, and forming a flattening layer on the ridge. A grating is then formed on the flattening layer and the grating is further transferred to the laser substrate on which the ridge is formed. The flattening layer is removed and electrodes are then formed.

Abstract: A semiconductor laser includes an active layer made of semiconductor; a ridge stripe having a cladding layer formed on the active layer and a contact layer formed on the cladding layer to protrude from the active layer; a pair of gratings each having a periodic structure in a longitudinal direction of the ridge stripe having a plurality of grooves each extending from side walls of the ridge stripe on flat portions in both sides of the ridge stripe; and absorbing layers covering the surfaces of the grooves of gratings to absorb excited light.

Abstract: A distributed feedback semiconductor laser including a semiconductor substrate having a bottom surface and a top surface; an active layer formed on the top surface of the semiconductor substrate; a ridge stripe formed on the active layer having a first surface and extending in a first direction; a periodic structure that is periodic in the first direction; a plurality of p-type electrodes formed on the first surface of the ridge stripe; and an n-type electrode formed on the bottom surface of the semiconductor substrate. The first surface of the ridge stripe is parallel with a growth plane of the active layer, the first surface having at least two different widths in a direction perpendicular to the first direction.

Abstract: There is provided a method of manufacturing a ridge type LC-DFB semiconductor laser in which a laser substrate having a cladding layer made of a material for a ridge stripe formed on an active layer made of semiconductor. A stripe mask is formed on the cladding layer to form two lateral flat portions from the cladding layer, by a selective wet etching, so as to form a ridge stripe protruding therefrom and having a flat top portion at which the stripe mask capped. A grating mask is formed on the two lateral flat portions, side walls of the ridge stripe and the stripe mask. The grating mask has a periodic structure in the direction in which the ridge stripe extends.