Title:
LOCK DETECTOR AND OPTICAL PHASE LOCKED-LOOP SYSTEM
Document Type and Number:
WIPO Patent Application WO/2006/041103
Kind Code:
A1
Abstract:
A lock detector for detecting lock of an optical phase locked-loop device. The lock detector comprises a first phase detector for comparing the phases of an input optical signal and a beat optical signal and outputting a first phase comparison signal, a loop filter for shaping the first phase comparison signal, and an optical voltage-controlled oscillator for outputting the beat optical signal according to the shaped first phase comparison signal. The lock detector is characterized in that it further comprises a phase shifter for shifting the phase of the beat optical signal and a second phase shifter for comparing the phases of the input optical signal and the beat optical signal the phase of which has been shifted and outputting a second phase comparison signal and in that the phase shifter shifts the phase of the beat optical signal to an extent that the phase comparison signal is not zero when the phases of the two optical signals compared by the second phase detector are locked.
Inventors:
TAKASAKA SHIGEHIRO (JP)
OZEKI YASUYUKI (JP)
OZEKI YASUYUKI (JP)
Application Number:
PCT/JP2005/018806
Publication Date:
April 20, 2006
Filing Date:
October 12, 2005
Export Citation:
Assignee:
JAPAN SCIENCE & TECH AGENCY (JP)
FURUKAWA ELECTRIC CO LTD (JP)
TAKASAKA SHIGEHIRO (JP)
OZEKI YASUYUKI (JP)
FURUKAWA ELECTRIC CO LTD (JP)
TAKASAKA SHIGEHIRO (JP)
OZEKI YASUYUKI (JP)
International Classes:
H03L7/095; G02F2/00
Domestic Patent References:
| WO2003104886A1 | 2003-12-18 |
Foreign References:
| JPH01126631A | 1989-05-18 | |||
| JPH08288902A | 1996-11-01 |
Other References:
SALEM R. ET AL: "Broad-Band Optical Clock Recovery System Using Two-Photon Absorption", IEEE PHOTONICS TECHNOLOGY LETTERS, vol. 16, no. 9, 2004, pages 2141 - 2143, XP001212336
YANO T. ET AL: "Hikari PLL Clock Chushutsu Hoshiki o Mochiita Hikari TDM20Gb/s-105km Denso Jikken.", THE INSTITUTE OF ELECTRONICS, INFORMATION AND COMMUNICATION ENGINEERS SHUNKI TAIKAI KOEN RONBUNSHU, vol. S-8-8, 10 March 1994 (1994-03-10), pages 4-445 - 4-446, XP002999612
See also references of EP 1806617A4
YANO T. ET AL: "Hikari PLL Clock Chushutsu Hoshiki o Mochiita Hikari TDM20Gb/s-105km Denso Jikken.", THE INSTITUTE OF ELECTRONICS, INFORMATION AND COMMUNICATION ENGINEERS SHUNKI TAIKAI KOEN RONBUNSHU, vol. S-8-8, 10 March 1994 (1994-03-10), pages 4-445 - 4-446, XP002999612
See also references of EP 1806617A4
Attorney, Agent or Firm:
Arafune, Hiroshi c/o KOYO INTERNATIONAL PATENT AND LAW FIRM (5F. Nikko Kaguraza,a Bldg., 18, Iwatocho, Shinjuku-ku Tokyo 32, JP)
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