Title:
光通信の改良または光通信に関連した改良
Document Type and Number:
Japanese Patent JP2004516743
Kind Code:
A
Abstract:
A method of transmitting a plurality n data streams comprises modulating an optical carrier using differential M -ary phase shift key (DMPSK) signaling in which M =2 n . Advantageously the method comprises using differential quaternary phase shift keying in which n=2. A particular advantage of the method of the present invention is that since the data is differentially encoded in the form of phase changes rather than absolute phase values this enables the modulated optical carrier to be demodulated using direct detection without requiring a phase-locked local optical oscillator. The invention is particularly applicable to WDM communication systems.
Inventors:
Robert Griffin
Application Number:
JP2002552220A
Publication Date:
June 03, 2004
Filing Date:
December 18, 2001
Export Citation:
Assignee:
Bookham Technology PLC
International Classes:
H04B10/556; H04J14/00; H04J14/02; H04L25/03; (IPC1-7): H04B10/04; H04B10/06; H04B10/142; H04B10/152; H04J14/00; H04J14/02
Domestic Patent References:
| JPH03179939A | 1991-08-05 | |||
| JP2000092001A | 2000-03-31 | |||
| JPS6386608A | 1988-04-18 | |||
| JPS631220A | 1988-01-06 | |||
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| JPH11331089A | 1999-11-30 | |||
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Other References:
RICHARD GROSS 他: "Optical DQPSK Video System with Heterodyne Detection", PHOTONICS TECHNOLOGY LETTERS, vol. 3, no. 3, JPNX007031891, March 1991 (1991-03-01), US, pages 262 - 264, ISSN: 0000864657
RICHARD GROSS 他: "Optical DQPSK Video System with Heterodyne Detection", PHOTONICS TECHNOLOGY LETTERS, vol. 3, no. 3, JPN7008005689, March 1991 (1991-03-01), US, pages 262 - 264, ISSN: 0001092027
RICHARD GROSS 他: "Optical DQPSK Video System with Heterodyne Detection", PHOTONICS TECHNOLOGY LETTERS, vol. 3, no. 3, JPN7008005689, March 1991 (1991-03-01), US, pages 262 - 264, ISSN: 0001092027
Attorney, Agent or Firm:
Masatake Shiga
Tadashi Takahashi
Takashi Watanabe
Masakazu Aoyama
Suzuki Mitsuyoshi
Kazuya Nishi
Yasuhiko Murayama
Shinya Mitsuhiro
Tadashi Takahashi
Takashi Watanabe
Masakazu Aoyama
Suzuki Mitsuyoshi
Kazuya Nishi
Yasuhiko Murayama
Shinya Mitsuhiro