Nippon Telegraph and Telephone Corporation

Hamamatsu-Photonics K.k.

Nippon Telegraph and Telephone Corporaiton

Haruhiko Ichino

Masaki Hirose

Kenji Kawai

Yoshihisa Warashina

Mikio Kyomasu

Osamu Ishida

Kazuhiko Terada

Noboru Ishihara

Keiji Kishine

A method and apparatus for synchronous frame communication first communicates a frame signal having communication data and first control information having a bit length and an SDH frame structure in a part of frame time interval and a control information processing method based on an SDH-frame-overhead-process for processing the first control information that includes bytes indicative of each of a relay node's section overhead, an end terminal section overhead, and at least a part of a byte of higher path's overhead. In the frame time interval a signal is communicated by a different second communicating method having the communication data and second control information having a bit length capable of including a significantly higher amount of information than that of the first control information and which corresponds to the first control information byte communicated in the frame time interval.

Method and apparatus for synchronous frame communication

A clock/data recovery circuit used in a receiving apparatus is provided in the circuit including: a voltage control oscillator for generating a clock signal of a frequency of 1/K of a bit rate of an input data signal; a delay circuit; a demultiplexer for demultiplexing the input data signal; a multiplexer for multiplexing the demultiplexed signals; a phase comparator for comparing phases of an output signal of the delay circuit and an output signal of the multiplexer; a lowpass filter; wherein the clock/data recovery circuit outputs the clock signal generated by the voltage control oscillator as a recovery divided clock signal, and outputs the demultiplexed signals output as recovery parallel data signals.

Clock/data recovery circuit

In a transmission node, a portion of the control information is separated into M (M is an integer) parts of control information blocks having N (N is an integer) bit length. A control information parity having (8&#x2212;N) bit length is added to control information block i. The control information block is encoded to M parts of control information having 8 bit length according to a predetermined control information bit array. The control information parity and the control information bit array are set such that Hamming distance of each of the control information code is d, and Hamming distance of the control information 10B code is D (d and D are integers). In a receiving node, the control information code is separated into the control information block and the control information parity. Parity check is performed. When an error is detected, error processing is performed.

Encoding method and apparatus for forward error correction

A light emitting unit including a light emitting device of a light emitting module for optical communication is constituted by a laser diode for emitting communication light, a sub-mount having a good thermal conductivity and holding the laser diode on its upper surface, a heat sink for removing the heat generated by the laser diode, a photodiode for monitoring a light output from the laser diode, a laser driver IC which is thermally isolated from the laser diode, has an electric contact placed near the electric contact of the laser diode and connected thereto by wire bonding, and drives the laser diode, and a metal package for holding the heat sink, the photodiode, and the laser driver IC. A light emitting module for optical communication uses the light emitting unit.

Light transmitting module for optical communication and light

A photodetector unit for a photodetector module for optical communication includes a photodetector circuit unit constituted by a ceramic board on which a photodiode for converting input light into an electrical signal and a preamplifier IC connected to the photodiode by bump bonding are mounted, and which has a photodetector circuit connected to the preamplifier IC by bump bonding, and a main amplification circuit unit constituted by a ceramic board on which a main amplification IC is mounted, and which has a main amplification circuit connected to the main amplification IC by bump bonding. The ceramic boards of the photodetector circuit unit and the main amplification circuit unit are mechanically and electrically connected to each other such that a mount surface of the preamplifier IC becomes perpendicular to a mount surface of the main amplification IC.

Light receiving module for optical communication and light receiving

An amplifier circuit of this invention includes a first-stage amplifier, an amplifier element connected to the output terminal of the first-stage amplifier as a feedback load, and a further amplifier element connected between the output and input terminals of the amplifier element, and performs negative feedback through a load of the first-stage amplifier. As the amplifier element, a transistor is used, and as the further amplifier element, an emitter-follower transistor is used.

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Tokyo, Japan

Haruhiko Ichino