Sony Corporation

Sharp Kabushiki Kaisha Corporation

Kuninori Shino

Kazuyoshi Horie

Hideki Yoshida

Yoichi Toriumi

Satoshi Kusaka

Kei Sato

Kenichi Ookubo

Akihiko Memezawa

Youichi Toriumi

Hiroshi Ohki

Shigeo Kubota

Isao Kawashima

Masakazu Ukita

Yoshinobu Kure

Kazuhito Nagura

Yohei Kawamoto

Tamotsu Ishii

Yoshifumi Masuda

Takuya Hirano

Keisuke Sekiguchi

Hideo Hara

Kimihiro Saitou

Yoshimoto Omura

Keniti Ookubo

In a quantum cryptography communication apparatus, a light pulse is generated by a light source and split into a signal light pulse and a reference light pulse on a receiving side. The signal light pulse and the reference light pulse are transmitted to a sending side via a communication channel. On the sending side, the received reference light is passed through a first optical path and phase-modulated by a randomly selected amount. Communication information is acquired on the basis of the reference light passed through the first optical path and the signal light passed via a second optical path. Frequencies of the signal light pulse and the reference light pulse are shifted. The intensity of the signal light pulses is attenuated and phase-modulated by an amount corresponding to the communication information. The resultant signal light pulse and the reference light pulse are returned back to the receiving side.

Quantum cryptography communication apparatus and communication terminal

An optical communication apparatus in which bidirectional communication may be made over a sole optical fiber. A light emitting device () radiates light through an optical system () to an optical fiber (). The light transmitted from the optical fiber () is received over optical system () by a light receiving device (). In the optical system (), such a relationship S&#x2212;2QN&#x2267;M&#x3e;S/2Q&#x2212;N is set, where M is the light volume of the stray light emitted, Q is the value of a Q-value representing the communication quality as required, S is the light volume of a received signal from a communication partner and N is the sum total of the Gaussian noise.

Optical communication method and apparatus

An optical communication system suitable for full duplex optical communication between a first and a second optical transceiver units. connected with each other by a single-core optical fiber. The first and second transceiver units may have different types of light emitting elements emitting light having different loss rates in the single-core optical fiber. The system enables stable full duplex communication without setting up large scale or costly transmission units by relatively reducing the optical crosstalk involved. The first optical transceiver unit provides transmission light to be coupled with the single-core optical fiber with the intensity in the range of TAmin&#x2013;TAmax. The amount of light emitted from the light emitting element of the optical transceiver unit to be coupled with the single-core optical fiber is in the range TBmin&#x2013;TBmax, which amount may be adjusted by a light emission adjusting unit provided in the optical transceiver unit.

Optical communication system

The invention provides an optical communication system, an optical transmitting apparatus, an optical receiving apparatus, an optical communication method, and a storage medium, in which a large-capacity transmission can be performed at high speed and multiplexing efficiency can be improved. The optical communication system includes an optical transmitting apparatus and an optical receiving apparatus connected via a transmitting medium having anomalous dispersion characteristics. In this system, the optical transmitting apparatus converts a plurality of information signals output from a plurality of signal sources into light signals having amplitudes different according to the respective information signals to output the light signals LP, by providing an individual specified optical intensity capable of performing an optical soliton transmission. The optical receiving apparatus has a function of demodulating the light signals LP input via the transmitting medium by identifying the corresponding information signal according to the magnitude of the amplitude to demodulate the plurality of the information signals.

Optical communication system, optical transmitting apparatus, optical receiving apparatus, optical communication method, and storage medium

A first surface of an optical component has a lens function of converging the transmission light from a light source. A second surface reflects the transmission light, converged by the lens function of the first surface, towards an end face of an optical transmission medium as the destination of transmission. The light reflected by the second surface is radaited from a coupling surface. Since the light beam from the light source is directed towards the optical transmission medium by exploiting the total reflection of light, a high-reflection multi-layer film or a polarization beam splitter film, required in a conventional apparatus employing a polarization beam splitter, is unneeded, with the result that the film forming cost or the cost in bonding two prisms used for fabricating the polarization beam splitter may be dispensed with. In this manner, the production cost or size of the apparatus can be reduced without lowering the transmission/reception performance.

Optical apparatus

The invention provides an optical communication apparatus to communicate a data signal. The optical communication apparatus is capable of firmly carrying out optical communication using an optical transmission media. The optical transmission media may be connected between a first optical communication apparatus and a second optical communication apparatus. Upon a detector detecting an incoincidence between an electric signal outputted from a light receiving element and a test signal, a controller may control a parameter of a light emitting power control signal to increase an intensity of an optical signal outputted from a light emitting element. Upon the detector detecting a coincidence therebetween, the controller may set a current value of a parameter of the light emitting power control signal as a parameter upon a selector selecting the data signal.

Optical communication apparatus

An optical fiber connecting method and apparatus in which optical communication is performed in a uni-core bidirectional system as optical crosstalk is prevented from occurring. To this end, an optical fiber connector includes a refractive index matching member and an optical fiber connecting unit . The refractive index matching member has a refractive index substantially equivalent to that of the cores of optical fibers . The optical fiber connecting unit interconnects the optical fibers in a state in which end faces of the optical fibers are contacted with a refractive index matching member interposed between the end faces of the optical fibers

Optical fiber connecting device, electronic equipment, network system and optical fiber connecting method

A first surface of an optical component has a lens function of converging the transmission light from a light source. A second surface reflects the transmission light, converged by the lens: function of the first surface, towards an end face of an optical transmission medium as the destination of transmission. The light reflected by the second surface is radaited from a coupling surface. Since the light beam from the light source is directed towards the optical transmission medium by exploiting the total reflection of light, a high-reflection multi-layer film or a polarization beam splitter film, required in a conventional apparatus employing a polarization beam splitter, is unneeded, with the result that the film forming cost or the cost in bonding two prisms used for fabricating the polarization beam splitter may be dispensed with. In this manner, the production cost or size of the apparatus can be reduced withut lowering the transmission/reception performance.

An optical transmitter-receiver according to the present invention is an optical transmitter-receiver connected to an optical fiber used for a single-core two-way optical communication channel for making a first optical signal S to be sent incident upon the end of the optical fiber and receiving a second optical signal S sent via the optical fiber. The above optical transmitter-receiver is provided with emission means for emitting a first optical signal S an optical system for making a first optical signal S from the emission means incident upon the incident end of the optical fiber in a direction R different from a direction in which a second optical signal S is outgoing from the end of the optical fiber and light receiving means for receiving a second optical signal S outgoing from the end of the optical fiber.

Optical transmitter-receiver and optically sending/receiving method

Disclosed is an optical disc apparatus compatible with both ROM type and RAM type optical discs having high density and large capacity. An optical disc apparatus includes: a disc control device including an optical disc (a magneto-optical disc), a spindle motor for rotating the optical disc, an objective lens for forming a light spot on the optical disc, and a control drive device which controls and drives the objective lens in the tracking direction of the optical disc, a semiconductor laser serving as a light source, a signal light transfer having a polarization-preserving optical fiber for guiding output light from the semiconductor laser to the objective lens, &frac14; wave plates provided in optical paths on both sides of the polarization-preserving optical fiber, and signal detecting devices (polarization beam splitter and photo detectors) for detecting a servo signal, etc. from the reflected light from the optical disc.

Optical disc apparatus

A recording and/or reproducing method for using an optical disc in the recording or reproduction data on or from the optical disc in predetermined data-length units. In a recording operation, the recording and/or reproducing method includes the step of dividing data read from the optical disc in the predetermined sector length, rewriting inputted data into the desired sector which is divided from the predetermined data-length inputs and recording the data including the rewritten sector on the optical disc in the predetermined data-length units. In a reproducing operation, the recording and/or reproducing method includes the step of reading the data having from the optical disc in the predetermined data-length units, dividing the data read from the optical disc in the predetermined data-length units into the predetermined sector length and transferring data of the reproduced desired sector as output data.

Recording and/or reproducing method for an optical disc

Optical card recording apparatus

Apparatus for controlling a tone arm is provided with a horizontal drive motor for moving the tone arm in the horizontal direction, a horizontal velocity detector connected to the same rotating shaft as the tone arm so as to move concurrently with both the tone arm and the horizontal drive motor, a control circuit having a motional feedback loop to energize the horizontal drive motor in accordance with a desired pre-set velocity signal and a fedback detected velocity signal.

Tone arm assembly

A tone arm assembly provided with a motor for moving a tone arm in a horizontal direction with respect to a record disc, a servo circuit for keeping the moving velocity of the tone arm constant, and a positioning servo circuit to operate when the tone arm reaches a reproducing position, in which the positioning servo circuit and the velocity controlling servo circuit are combined together thereby to stop the tone arm quickly at a predetermined position.

A tone arm assembly for record players has first and second electro-magnetic motors operable for swinging a tone arm in vertical and horizontal directions, respectively, in respect to a record disc on a turntable, and a control circuit for controlling the first and second motors in such a manner that the tone arm is moved from a raised inoperative position to a lowered playing position, or from the lowered playing position to the raised inoperative position in response to control signals.

Growing community of inventors

Tokyo, Japan

Kuninori Shino