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NTT Electronics Corporation Patents
NTT Electronics Corporation
Tokyo, JP
No. of patents:

Patent Number Title Of Patent Date Issued
8575650 Avalanche photodiode November 5, 2013
An electron injected APD with an embedded n electrode structure in which edge breakdown can be suppressed without controlling the doping profile of an n-type region of the embedded n electrode structure with high precision. The APD comprising a buffer layer with a low ionization rate
8571037 Optical digital transmission system October 29, 2013
An optical digital transmission system of the present invention newly defines one second negative stuff byte in an overhead area for accommodation of the client signals with multiplexing into the OTU frame, newly defines one third positive stuff byte in a corresponding tributary slot
8569674 Multiplexed photocurrent monitoring circuit comprising current mirror circuits October 29, 2013
A low cost photocurrent monitoring circuit is provided. A photocurrent monitoring circuit, which performs monitoring by converting photocurrents output from a plurality of photodiodes (PD1 to PDn) into voltage, includes: a multiplexer circuit (MUX) for selecting one of input terminal
8204105 Transcoder and coded image conversion method June 19, 2012
A quantization step determination part inputs an evaluation value (ACT_MB) indicating the dispersion in a macroblock and its average value (ACT_PIC). A subtracter obtains the difference between these values, and a multiplier multiplies the difference by (<1) to obtain a w
8102888 Semiconductor laser device and driving method of the same January 24, 2012
A semiconductor laser device according to the present invention outputs light while periodically varying the temperature of a semiconductor laser, an optical waveguide, or a diffraction grating, outputs light while causing the optical waveguide or the diffraction grating to mechanica
8094692 Modulation method, modulation program, recording medium, modulation device, and optical transmit January 10, 2012
A modulation method according to the invention is applied to a modulation device in which a light source is driven by a differential signal while a modulation circuit and the light source are capacitively coupled. In the modulation method of the invention, when an average potential fluct
8031984 Semiconductor optical modulator October 4, 2011
The present invention can provide an npin-type optical modulator that has a high withstand voltage and is easily fabricated. A semiconductor optical amplifier (10) according to an embodiment of the present invention is an npin-type semiconductor optical modulator in which layers are
7995930 Optical receiver using Mach-Zehnder interferometer August 9, 2011
The present invention relates to an optical receiver, in which the transmittance of a Mach-Zehnder interferometer can be locked at a normal operation point in a simple structure and control. A transmittance detecting circuit and a minute modulation signal detecting circuit are provid
7995876 Arrayed waveguide grating circuit August 9, 2011
Two AWG circuits are integrated while preventing degradation in quality of a multiplexing/demultiplexing function. An arrayed waveguide grating circuit includes: a first slab waveguide (52) connected to a first input waveguide (51a) and second output waveguides (55b); a second slab w
7936842 Automatic bit rate control circuit May 3, 2011
A bit-rate automatic control circuit for feedback controlling the gain and bandwidth of a preamplifier in dependence on the bit-rate of a signal is disclosed. The circuit includes a bit-rate discrimination circuit configured to discriminate the bit rate of the signal, and an alarm ci
7881414 Bit rate discrimination circuit based on a low frequency component of signal February 1, 2011
A bit-rate discrimination circuit for determining which bit-rate an input signal has, a first bit-rate or a second bit-rate higher than the first bit-rate, is disclosed. The circuit is characterized by a frequency selection unit configured to filter out a signal having the second bit
7880197 Avalanche photodiode having doping region with monotonically increasing concentration distributi February 1, 2011
In an electron-injection type APD, it is necessary to prevent a dark current increase and to secure the life time of the device. It is demanded to improve reliability of the APD with a lower production cost. With the InP buffer layer having an n-type doping region on the inside of a
7868701 Transimpedance amplifier January 11, 2011
A gain switching determination circuit (250) compares/determines a comparative input voltage (Vc) from an inter-stage buffer (230) with a first hysteresis characteristic, and outputs a gain switching signal (SEL) based on the comparison/determination result to first and second transi
7808705 Wavelength-selective switch October 5, 2010
A wavelength-selective switch with a switch unit having a lens array, a first lens and a beam expander, and a branching unit having a second lens, a diffraction grating, a third lens and a mirror, in which the switch unit and the branching unit are accommodated in independent casings
7787736 Semiconductor optoelectronic waveguide August 31, 2010
The present invention relates to a semiconductor optoelectronic waveguide having a nin-type hetero structure which is able to stably operate an optical modulator. On the upper and lower surfaces of the core layer determined for the structure so that electro-optical effects are effect
7729585 Light source apparatus with modulation function and its driving method June 1, 2010
A light source apparatus with modulation function has a wavelength conversion module (75) composed of a nonlinear optical material with a structure having a nonlinear constant modulated periodically. It outputs a difference frequency or sum frequency produced by multiplexing pumping
7714751 Transcoder controlling generated codes of an output stream to a target bit rate May 11, 2010
A transcoder calculates a reference conversion factor on the basis of a ratio between a total target bit rate of a whole second stream and an total input bit rate of a whole first stream and calculates a coefficient of variation from the total target bit rate of the whole second stream
7599595 Semiconductor optoelectronic waveguide October 6, 2009
The present invention relates to a semiconductor optoelectronic waveguide having a nin-type hetero structure which is able to stably operate an optical modulator. On the upper and lower surfaces of the core layer determined for the structure so that electro-optical effects are effect
7599587 Wavelength selective switch October 6, 2009
In a wavelength selective switch according to the present invention, an isolator is disposed between a lens array and a first lens. The isolator includes an isolator element and a transmitting means. The isolator is disposed so that the isolator element is on light paths of input lights
7557387 Avalanche photodiode July 7, 2009
An ultra high speed APD capable of realizing reduction in an operating voltage and quantum efficiency enhancement at the same time is provided. Under operating conditions APD, a doping concentration distribution of each light absorbing layer is determined so that a p-type light absorbing
7499613 Y branch circuit and method for manufacturing the same March 3, 2009
A Y branch circuit according to the present invention includes; a under clad; a circuit core, formed on the under clad and having a main core and two branch cores, connected to the main core, and an over clad that embeds the circuit core. The main core and the two branch cores are co
7413355 Light emitting module and single-fiber two-way optical communication module August 19, 2008
A light emitting module according to the present invention is characterized in that a light emitting device and a light-emission-side lens are held close to each other by a holding part extended from part of a stem in parallel with outgoing light of the light emitting device, and lig
7400800 Arrayed waveguide grating type optical multiplexer/demultiplexer circuit July 15, 2008
An arrayed waveguide grating type optical multiplexer/demultiplexer circuit in which wavelength dispersion is reduced. An input wave guide (1), a first slab waveguide (2), an arrayed waveguide (3), a second slab waveguide (4) and an output waveguide (5) are connected sequentially. Fu
7364370 Optical receptacle and optical module with optical receptacle April 29, 2008
An optical receptacle according to the invention includes a columnar stub ferrule having an optical fiber inserted into a center line connecting both opposite end faces; a cylindrical sleeve into which a part of the stub ferrule is inserted; and a housing in which a through hole is f
7261471 Optical connector having shielding mechanism August 28, 2007
There is provided an optical connector device which prevents leakage of light until right before connectors are connected to each other and is small-sized by a reduction in space for housing shutters. The optical connector device is an optical connector device comprising a first opti
7257184 Phase comparator, clock data recovery circuit and transceiver circuit August 14, 2007
A phase comparator comprises a latch unit for latching the input data signal in parallel on rising/falling edges of the respective clock signals respectively, an error signal output unit for outputting m error signals respectively indicative of differences in phase between the transi
7092593 Microactuator device and optical switching system using the same August 15, 2006
A movable plate is fastened to a substrate via flexure parts and can move upward and downward with respect to the substrate. The substrate serves as a fixed electrode. The movable plate has second electrode parts which generate an electrostatic force between these electrode parts and the
7086789 Optical element module with a primary coated optical fiber August 8, 2006
An optical element module is equipped with a casing, an optical element provided inside the casing, a pipe which communicates the inside of the casing to the outside, and a primary coated optical fiber which is inserted through the pipe and connected to the optical element.
7082251 Optical device July 25, 2006
An optical device is configured such that an insertion plate is held by a flat cantilever having electric wiring, and the flat magnet is placed in such a manner that the magnet faces a surface of the cantilever opposite to the other surface of the cantilever facing an optical waveguide,
7054403 Phase-Locked Loop May 30, 2006
A phase lock circuit has a signal path to which a phase comparator, a loop filter and a voltage control oscillator are connected in series, the phase comparator being adapted to compare the phase of an input signal V.sub.IN with the phase in the output signal of the voltage control o
7050673 Temperature control device and arrayed waveguide grating optical wavelength multiplexer/demultip May 23, 2006
In a temperature control device which maintains an object to be controlled at a preset constant temperature and an arrayed waveguide grating optical wavelength multiplexer/demultiplexer, the adverse effect of the junction temperature of the semiconductor control element is eliminated for
7045379 Method of manufacturing surface shape recognition sensor May 16, 2006
In a method of manufacturing a surface shape recognition sensor, first and second interconnections are formed on a semiconductor substrate. An interlayer dielectric film on the semiconductor substrate covers the interconnections. A first metal film is electrically connected to the in
7010200 Light-beam switching/adjusting apparatus and manufacturing method thereof March 7, 2006
The light guide substrate 2 has mirror receiving grooves 24 and light guides. The light guides conduct light that is input into the input ports to selected output ports in accordance with the advance and retraction of the mirrors 31 with respect to the grooves 24. The actuator substrate
7006722 Waveguide type optical device and position detecting method February 28, 2006
A waveguide type optical device performs such monitoring as detection of a relative position of an insert plate to a groove. The waveguide type optical device comprises a groove disposed at an intersection position of a first optical waveguide and a second optical waveguide; an insert pl
6985667 Optical fiber component for connection and manufacturing method thereof January 10, 2006
This invention provides an optical fiber wiring board having excellent optical property, high reliability and high mounting property. This invention relates to an optical fiber component for connection having a substrate on which a plurality of optical fibers being wired, wherein a f
6954562 Matrix switch of optical waveguide type and method for manufacturing the same October 11, 2005
A matrix switch of an optical waveguide type which has low transmission loss variations and includes uniform grooves with a deep vertical cross section is provided. A switching part for selecting between a light path extending from an input port of a first set of optical waveguides
6912083 ASE light source, optical amplifier and laser oscillator June 28, 2005
An ASE light source offers high outputs even in a wavelength band of 1,490 to 1,525 nm. The ASE light source outputs spontaneous emission light generated from Tm-doped optical fibers. Then, the ASE light source outputs amplified light obtained by using Er-doped optical fibers to amplify
6909161 Photodiode June 21, 2005
A photodiode has an optical absorption layer composed of a depleted first semiconductor optical absorption layer with a layer width W.sub.D and a p-type neutral second semiconductor optical absorption layer with a layer width W.sub.A. The ratio between W.sub.A and W.sub.D is set such tha
6904204 Array waveguide diffraction grating type optical multiplexer/demultiplexer June 7, 2005
An object of this invention is to cancel a polarization dependence of a transmission center wavelength due to the waveguide birefringence in an array waveguide and a slab waveguide in an array waveguide diffraction grating type optical multiplexer/demultiplexer filter applied for optical
6898345 Optical multiplexer and method for its production May 24, 2005
An optical multiplexer is equipped with at least one input channel optical waveguide provided on an optical waveguide substrate, a first slab optical waveguide, a channel optical waveguide array formed from a plurality of optical waveguides having a prescribed waveguide length, a second
6888379 Phase comparator circuit May 3, 2005
A phase detector circuit that prevents a significant loss of lock during input of CIDs (Consecutive Identical Digits) and has a high linearity of a phase to voltage conversion characteristic around a phase-locked point in an operation of comparing phases of random NRZ signals in a phase.
6885823 Wavelength multiplexing/demultiplexing unit, wavelength multiplexing/demultiplexing apparatus an April 26, 2005
An optical multiplexing/demultiplexing apparatus in which a plurality of optical multiplexing/demultiplexing units operating in different wavelength bands are connected hierarchically. Each of the plurality of optical multiplexing/demultiplexing units includes an input waveguide for
6879607 Semiconductor laser module April 12, 2005
A problem of the present invention is to provide a semiconductor laser module for making precise temperature control possible.A semiconductor laser module 1 according to the present invention has a Peltier element 4, a thermistor 5 for detecting the temperature of the Peltier element 4,
6842560 Optical multiplexing circuit and optical multiplexer January 11, 2005
A part of a wavelength division multiplexed optical signal output from a multiplexing area is extracted as a check signal, and then the extracted signal is guided to a multiplexing area. A reentered check signal is detected at a facet located opposite a facet from which the check signal
6731780 Fingerprint image judgment apparatus and program May 4, 2004
A fingerprint image judgment apparatus is capable of judging whether or not fingerprint image data has been correctly read when a CPU having a small utilizable memory space is used. A first count unit counts the number of ridges or valleys in one direction of an X-axis direction or a Y-a
6678290 Optical output control circuit for obtaining stable optical output power January 13, 2004
According to the present invention, an optical output automatic control circuit includes an optical output cutoff control circuit outside its feedback loop, and sets an optical output setting voltage at the ground level to prevent overshoot of the optical output while an optical output
6476919 Polarization-independent reflectometry and polarization-independent reflectometer November 5, 2002
Emitted light from a light source 1 is separated into two parts through an optical fiber coupler 2, one is entered in a measured optical module 3 as measurement light, and the other is given a group delay by means of an optical fiber delay line 5, a reflector 25, etc., as local light sig
6304687 Optical waveguide circuit, its manufacturing method and optical waveguide module having the opti October 16, 2001
In a light waveguide circuit including a plurality of waveguides having different length, a material (10) having a temperature coefficient of a refractive index including a symbol different from that of a temperature coefficient of an effective refractive index of the waveguide (4) is
6229165 Semiconductor device May 8, 2001
This invention provides a semiconductor device including a silicon layer, an insulating layer formed on the silicon layer, a first semiconductor device formed on the insulating film to convert light into an electric signal, and a second semiconductor device formed on the insulating film,
6160544 Digital video distribution system December 12, 2000
A digital video distribution system is disclosed which includes video terminals connected within a LAN and distributes video from a certain terminal to destination terminals, simultaneously. In this system, each transmitter terminal has an encoder that converts analog video information

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