Abstract: Measuring of an electro-optic coefficient and a thermo-optic coefficient of an optical device and an optical material, and more specifically, to measurement systems and methods of evaluating the electro-optic and thermo-optic coefficients by using interference fringe measurement techniques, wherein those optical characteristics can be precisely measured over a wide wavelength intended without using a complicated measuring equipment.

Abstract: Measuring of an electro-optic coefficient and a thermo-optic coefficient of an optical device and an optical material, and more specifically, to measurement systems and methods of evaluating the electro-optic and thermo-optic coefficients by using interference fringe measurement techniques, wherein those optical characteristics can be precisely measured over a wide wavelength intended without using a complicated measuring equipment.

Abstract: A single mode surface emitting laser and its manufacturing method are provided. The surface emitting laser which has a characteristic of single transverse mode radiation in the broad region using reflectivity distribution of a reflector layer with an antiguide clad is provided.

Abstract: A method for manufacturing quantum wires is provided in which a stacked structure having AlAs layers and GaAs layers alternatively is formed, V-grooves are formed beside the GaAs layers and the quantum wires are formed using the V-grooves.

Abstract: An optical fiber Raman laser includes an optical fiber which is a nonlinear optical medium, for implementing a nonlinear Stokes frequency shift; a wavelength-division multiplexing optical fiber coupler means, coupled to said optical fiber in parallel, for separating each Stokes frequency shifted wavelengths and pump wavelength, for internally resonating the Stokes frequency shited light wavelengths and for output-coupling said laser output light which is a second order Stokes frequency shifted wavelength; a first fiber Bragg grating means connected to said wavelength division multiplexing (WDM) optical fiber coupler means in serial, for transmitting light of the pump source and for selecting output wave of the Raman laser; and a second fiber Bragg grating means connected to said wavelength division multiplexing (WDM) optical fiber coupler means, which has maximum reflectivity on the wavelength of the pump source, for full-reflecting and re-inputting the light of the pump source to said optical fiber.

Abstract: An optical fiber Mach-Zehnder interferometer optical filter is disclosed.

Abstract: A multistage optical packet switching apparatus with self electro-optic-effect device is disclosed. The apparatus is formed with multistage structure using a plurality of symmetrical self electro-optic-effect devices, self-routing being performed by the control for a header part of optical packets after self-duplication and amplification for the input optical signal. The optical packet switching apparatus using a plurality of symmetrical self electro-optic-effect devices includes a front stage having first and second self electro-optic-effect devices interconnected and a back stage having third and fourth self electro-optic-effect devices interconnected, the 1.quadrature. multistage structure comprising the unit switching modules interconnected each comprising the front and the back stages, the self-duplication and amplification being performed in the front stage and the switching being performed in the back stage. The use of the apparatus is an optical exchange.

Abstract: An improved multi-wavelength channel transmission filter, by which it is possible to selectively and simultaneously separate multiple wavelength channel signals without any optical time delays among, different wavelength channels, includes one optical circulator with four terminal ports, one polarization beam splitter (PBS), one half-wave plate, and a number of Brag, gratings formed in an optical waveguide for reflection of multi-wavelength channels by combining the wavelength characteristic of each Bragg grating which is determined in accordance with the grating structure.

Abstract: A method of fabricating quantum wire structures and devices, and quantum dot structures and devices comprise steps of: depositing an insulating layer on a semiconductor substrate, forming a line patterns and a square patterns in an insulating layer, forming a V-grooved patterned structures and a reverse quadrilateral pyramid patterned structures by thermal etching to evaporate portions of the quantum well layer that are not protected by line-shaped mask regions and square-shaped mask regions of the masking layer, forming a quantum wires and a quantum dots by alternatively growing a barrier layer and an active layer on a V-grooved patterned substrate and a reverse quadrilateral pyramid patterned substrate.

Abstract: For a multiple transmission communication system, how to individually isolate the transmitted lights and then to distribute to the terminals has been primary concerns to be solved. In the photodetector structure, an absorption layer may be configured as either multiple quantum well structures corresponding to operational wavelengths, or filter-based structure, allowing to select wavelengths in a 1:2:4:8 ratio as an absorptance for each wavelength. In case of using such four-fold lights, the determination as to which wavelength among four-fold wavelengths can be made based upon the total amounts of the current flow in such a photodetector. The photodetector employing such schemes is provided from the present invention.

Abstract: The present invention provides a multi-wavelength channel transmission-type optical filter that is capable of more narrowing the bandwidth of transmission wavelength in a transmission type optical filter using Mach-Zehnder interferometer. The multi-wavelength channel transmission-type optical filter including a first optical fiber coupler for dividing a broadband light source into two lights, an optical fiber length and optical fiber length controlling unit for controlling the gap of transmission wavelength in which each receives as inputs the above lights divided by the first optical fiber coupler, a second optical fiber coupler for outputting each of the above lights, which are passed through the optical fiber length controlling unit and the optical fiber length, and an optical isolator for narrowing the width of transmission wavelength by connecting the two outputs of the second optical fiber coupler, thereby improving a wavelength selecting characteristics.

Abstract: The formation of self-assembled GaAs quantum dots on (100) GaAs via chemical beam epitaxy (CBE) technique using triethylgallium (TEGa) and arsine (AsH.sub.3) is disclosed. GaAs quantum dots are easy to grow from Ga-droplets which are successively supplied with arsine with neither pattern definition nor pre-treatment steps prior to the growth. The density and the size of Ga-droplets are found to be sensitive to the growth conditions, such as the growth temperature, the beam equivalent pressure of TEGa, and the amount of TEGa supplied. This invention suggests that, unlike Stranski-Krastanow growth, the Ga-droplet-induced CBE technique can be a useful method for the fabrication of quantum dot structure by simple change of gas supply mode, even in lattice-matched system.

Abstract: A linear motion apparatus for moving an object in a vacuum chamber comprising an antenna or a telescoping shaft such as a fishing rod to effectively utilize space, and to avoid the need of a rear projection thereby achieving stability.

Abstract: The present invention discloses an optical fiber laser and a method of harmonic mode locking utilizing the optical fiber laser, which is capable of locking a harmonic frequency occurred by inserting an optical modulator between a Faraday rotator mirror and a non-linear amplifying loop mirror to coincide the frequency component of the optical modulator with the frequency component of the longitudinal mode of the laser. In order to achieve the object of the present invention, it comprises an optical fiber laser which comprises a non-linear amplifying loop mirror, a linear mirror and an optical fiber directional coupler or fiber coupler.

Abstract: An epitaxial growth method for a compound semiconductor thin film, capable of forming a p-n junction with an atomic-scale ultra-micro structure is disclosed. The method involves loading the compound semiconductor substrate in a reaction chamber, injecting Group V and III metal organic source gases not processed by a thermal pre-decomposition process into the reaction chamber, and growing a p- or n-type compound semiconductor on the compound semiconductor substrate while adjusting the growth temperature of the p- or n-type compound semiconductor.

Abstract: A method for forming a highly dense quantum wire, the method comprising the steps of: depositing a dielectric mask having dielectric patterns on the top surface of a semiconductor (100) substrate; forming the dielectric patterns in parallel to a (011) orientation on the semiconductor substrate; exposing a (111)B side and a(111)B side by chemical etching a selected region between the patterns so that the semiconductor substrate has a dove-tail shape; forming a buffer layer on the dove-tail semiconductor substrate; forming the first barrier layer on the buffer layer; forming a well layer on the first barrier layer; and forming the second barrier layer on the well layer.

Abstract: Disclosed is a fabricating method of a GaAs substrate having a V-shaped groove in a higher density, that is a double density, the method comprising the steps of forming a Si.sub.3 N.sub.4 layer on a main surface of the GaAs substrate; patterning the Si.sub.3 N.sub.4 layer using a photo-lithography to form a patterned Si.sub.3 N.sub.4 layer having a minimum width; wet-etching the GaAs substrate using the patterned Si.sub.3 N.sub.4 layer as a mask, so as to form (111) and (100) surfaces of the GaAs substrate beneath the patterned Si.sub.3 N.sub.4 ; selectively growing a GaAs film on the GaAs substrate etched thus using the patterned Si.sub.3 N.sub.4 layer as a mask so as to form the GaAs film with two (111) facets only on a (100) surface of the GaAs substrate; and removing the Si.sub.3 N.sub.4 layer. The V-shaped grooves can be formed on a GaAs substrate utilizing a difference of growth rate caused by surface orientation of the substrate, and therefore the grooves can be formed in double density.

Abstract: A dual cavity laser having a positively mode-locked structure capable of double increasing the repetition rate of output light. The dual cavity laser includes an amplitude modulator to simultaneously generate two modulating signals with opposite phases. The dual cavity laser has a simply modified structure from that of the conventional single cavity laser to have two resonators, so that it can have a repetition rate corresponding to two times that of the single cavity laser. One of the resonators may have an adjusted optical property so as to obtain two kinds of output optical pulses with different optical properties.

Abstract: The wavelength tunable mode-locking optical fiber laser comprises non-linear amplifying loop mirror part having a light pumping lase diode, a gain medium doped optical fiber having the gain medium for oscillating the rambling light wave sequentially, a dispersion shifted optical fiber, and first polarization controller for making the continuous oscillation light wave to be maximized by adjusting the polarization of said propagating light. All elements of the non-linear amplifying loop mirror part are combined to each other in loop type on the above clock direction.

Abstract: A pulsed semiconductor laser has a lower threshold current and a more stable pulse train. The structure includes a saturable absorber section has a quantum well structure for laser oscillation, a gain section, a phase control section, and a super structure grating-distributed Bragg reflector section. It uses an improved construction for overcoming problems of conventional pulsed semiconductor lasers. The improved structure includes five quantum well layers having thicknesses with respective spontaneous emission peak wavelengths of ".lambda.-2.delta.", ".lambda.+.delta.", ".lambda.+2.delta.", ".lambda.", ".lambda.-.delta." at room temperature from their upper section. .lambda. denotes the mean wavelength of the oscillating pulse laser, and .delta. denotes a fixed value less than 12 nm.