This document describes an optical frequency comb generator comprising: an oscillator that oscillates modulating signals of a preset frequency, an optical resonator formed by parallel reflecting mirrors to cause resonance of incident light, and an optical phase modulation unit between the mirrors to phase modulate the resonant light using the modulating signals. This generates sidebands around the incident light frequency at intervals of the modulating signal frequency. The outgoing mirror transmittance is responsive to the sideband light intensities.

1. (12) United States Patent
Kourogi et al.
US007239442B2
US 7,239,442 B2
Jul. 3, 2007
(10) Patent N0.:
(45) Date of Patent:
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Jul. 26, 2001
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Oct. 31, 2001
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OPTICAL FREQUENCY COMB GENERATOR
Inventors: Motonobu Kourogi, 4-28-905,
Wakabadai, Asahi-ku, Yokohama-shi,
KanagaWa, 241-0801 (JP);
Widiyatmoko Bambang, KanagaWa
(JP); Osamu Nakamoto, Tokyo (JP);
Shigeyoshi MisaWa, Tokyo (JP);
Yoshinobu Nakayama, Tokyo (JP)
Assignees: Japan Science and Technology Agency
(JP); Motonobu Kourogi (JP)
Notice: Subject to any disclaimer, the term of this
patent is extended or adjusted under 35
U.S.C. 154(b) by 117 days.
10/484,598
Jul. 26, 2002
Appl. No.:
PCT Filed:
PCT No.:
§ 371 (0X1)’
(2), (4) Date:
PCT/JP02/07637
Aug. 30, 2004
PCT Pub. No.: WO03/010596
PCT Pub. Date: Feb. 6, 2003
Prior Publication Data
US 2005/0018276 A1 Jan. 27, 2005
Foreign Application Priority Data
(JP) ........................... .. 2001-226588
(JP) ........................... .. 2001-226591
(JP) ........................... .. 2001-334299
(JP) 2001-354947
(JP) 2002-038839
(JP) ........................... .. 2002-097167
Int. Cl.
H04B 10/17 (2006.01)
US. Cl. ..................................... .. 359/346; 359/333
Field of Classi?cation Search .............. .. 359/333,
359/346
See application ?le for complete search history.
IL
(56) References Cited
U.S. PATENT DOCUMENTS
3,676,796 A * 7/1972 Weber ....................... .. 372/19
(Continued)
FOREIGN PATENT DOCUMENTS
JP T94047 1/1996
JP 10-206919 8/1998
JP N99-0293 8/1998
JP 11-288009 10/1999
OTHER PUBLICATIONS
Saitoh et al. Modulation Characteristic of Waveguide-Type Optical
Frequency Comb Generator. Journal of Lightwave Technology, vol.
16, No. 5, May 1998. 824-832.*
(Continued)
Primary ExamineriJack Keith
Assistant ExamineriAri M. Diacou
(74) Attorney, Agent, or FirmiReed Smith, LLP
(57) ABSTRACT
An optical frequency comb generator includes an oscillator
(117) for oscillating modulating signals of a preset fre
quency, and an optical resonator (110) formed by an incident
side re?ecting mirror (112) and an outgoing side re?ecting
mirror (113), arranged parallel to each other. The optical
resonator causes resonation in light incident via the incident
side re?ecting mirror (112). The optical frequency comb
generator also includes an optical phase modulation unit
(111) arranged betWeen the incident side re?ecting mirror
(112) and the outgoing side re?ecting mirror (113) for phase
modulating the light, resonated by the optical resonator
(110), by the modulating signals supplied from the oscillator
(117), and for generating a plurality of sidebands centered
about the frequency of the incident light at a frequency
interval of the modulating signal. The outgoing side re?ect
ing mirror (113) sets the transmittance from one frequency
to another responsive to the light intensity of the generated
sidebands.
28 Claims, 27 Drawing Sheets
10
., 3I17 16
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2. US 7,239,442 B2
Page 2
US. PATENT DOCUMENTS
4,989,201 A * 1/1991 Glance ...................... .. 398/95
5,153,933 A * 10/1992 Smith et al. 385/27
5,166,822 A * 11/1992 Priatko et al. .. 359/287
5,265,112 A * 11/1993 Noll et al. .... .. 372/32
5,663,822 A * 9/1997 Fee .............. .. 398/95
5,699,378 A * 12/1997 Lealman et a1. 372/102
6,163,553 A * 12/2000 Pfeiifer . . . . . . . . . . . . . . . . . .. 372/6
6,201,638 B1* 3/2001 Hall et a1. .. 359/346
6,487,329 B2* 11/2002 FoltZer 385/15
6,591,026 B2* 7/2003 Endo et al. 385/15
6,724,788 B1 * 4/2004 HolZWarth et a1. . 372/32
6,897,959 B2* 5/2005 Haensch et al. 356/432
2005/0254534 A1* 11/2005 Loewen et al. ............. .. 372/32
OTHER PUBLICATIONS
Arthur Lowery. Performance Predictions and Topology
Improvements for Optical Serrodyne Comb Generators.
Journal ofLightWave Technology, vol. 23, No. 8, Aug. 2005.
2371-2379.*
In Kag HWang, Seok Hyun Yun, Byoung Yoon Kim. All
?ber nonreciprocal ?lter With wavelengthElEltunability.
OFC ’98 Technical Digest. 336-338.*
OptoComb technical datasheet/avertising brochure. Optical
Frequency Comb Generator. BK-SM 625C / BK-SM 2500C.
Optical Comb Institute, Inc. Tokyo Institute of Technology,
Incubation Center R204, 2-12-1, O-okayama, Meguro-ku,
Tokyo, 152-8550 Japan http://WWW.optocomb.com.*
OptoComb technical datasheet/avertising brochure.
Waveguide Optical Frequency Comb Generator. WTAS-01.
Optical Comb Institute, Inc. Tokyo Institute of Technology,
Incubation Center R204, 2-12-1, O-okayama, Meguro-ku,
Tokyo, 152-8550 Japan http://WWW.optocomb.com.*
M. Kourogi, T. Enami and M. Ohtsu. A Monolithic Optical
Frequency Comb Generator. IEEE Photonics Technology
Letters, vol. 6, No. 2, Feb. 1994. 214-217.*
M. Kourogi, T. Enami, and M. Ohtsu. A Coupled-Cavity
Monolithic Optical Frequency Comb Generator. IEEE
Photonics Technology Letters, vol. 8, No. 12, Dec. 1996.
1698-1700.*
T. Saitoh, M. Kourogi, and M. Ohtsu. A Waveguide-Type
Optical-Frequency Comb Generator. IEEE Photonics Tech
nology Letters, vol. 7. No. 2, Feb. 1995. 197-199.*
Jun Ye, Harald SchnatZ, and Leo W. Hollberg. Optical
Frequency Combs: From Frequency Metrology to Optical
Phase Control. IEEE Journal of Selected Topics in Quantum
Electronics, vol. 9, No. 4, Jul/Aug. 2003. 1041-1058.*
NeW Focus, Inc. Practical Uses and Applications of Electro
Optic Modulators. Application Note 2, Rev C, Copyright
2001. http://WWW.neWfocus.com/OnlineiCatalog/Litera
ture/apnote2.pdf. DLed: Jul. 5, 2006*
K. Imai; M. Kourogi; M. Ohtsu;i30-THZ Span Optical
Frequency Comb Generation by Self-Phase Modulation in
an Optical Fiber, IEEE Journal OfQuantum Electronics, vol.
34, No. 1, Jan. 1998, pp. 54-60.
M. Kourogi; T. Enami; M. Ohtsu;iA Coupled-Cavity
Monolithic Optical Frequency Comb Generator, IEEE
Photonics Technology Letters, vol. 8, No. 12, Dec. 1996, pp.
1698-1700.
Jun Ye; Long-Sheng Ma; Timothy Daly; John L.
Hall;iHighly selective terahertZ optical frequency comb
generator, Optics Letters, vol. 22, No. 5, Mar. 1, 1997, pp.
301-303.
M. Kourogi; T. Enami; M. Ohtsu;iA Monolithic Optical
Frequency Comb Generator, IEEE Photonics Technology
Letters, vol. 6, No. 2, Feb. 1994.
International Preliminary Examination Report (Translation).
K. Imai, M. Kourogi, M. Ohtsu “30-THZ Span Optical
Frequency Comb Generation by Self-Phase Modulation in
an Optical Fiber”, IEEE Journal Of Quantum Electronics,
vol. 34, No. 1, Jan. 1998, pp. 54-60.
M. Kourogi, T. Enami, M. Ohtsu “A Coupled-Cavity Mono
lithic Optical Frequency Comb Generator”, IEEE Photonics
Technology Letters, vol. 8, No. 12, Dec. 1996, pp. 1698
1700.
M. Kourogi, T. Enami, M. Ohtsu “A Monolithic Optical
Frequency Comb Generator”, IEEE Photonics Technology
Letters, vol. 6, No. 2, Feb. 1994, pp. 214-217.
European Search Report.
* cited by examiner

3. U.S. Patent Jul. 3, 2007 Sheet 1 0f 27 US 7,239,442 B2
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4. U.S. Patent Jul. 3, 2007 Sheet 2 0f 27 US 7,239,442 B2
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6. U.S. Patent Jul. 3, 2007 Sheet 4 0f 27 US 7,239,442 B2
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7. U.S. Patent Jul. 3, 2007 Sheet 5 0m US 7,239,442 B2
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8. U.S. Patent Jul. 3, 2007 Sheet 6 0f 27 US 7,239,442 B2
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9. U.S. Patent Jul. 3, 2007 Sheet 7 0m US 7,239,442 B2
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10. U.S. Patent Jul. 3, 2007 Sheet 8 0f 27 US 7,239,442 B2
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11. U.S. Patent Jul. 3, 2007 Sheet 9 0f 27 US 7,239,442 B2
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12. U.S. Patent Jul. 3, 2007 Sheet 10 0f 27 US 7,239,442 B2
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13. U.S. Patent Jul. 3, 2007 Sheet 11 0f 27 US 7,239,442 B2
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14. U.S. Patent Jul. 3, 2007 Sheet 12 0f 27 US 7,239,442 B2
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15. U.S. Patent Jul. 3, 2007 Sheet 13 0f 27 US 7,239,442 B2
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16. U.S. Patent Jul. 3, 2007 Sheet 14 0f 27 US 7,239,442 B2
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17. U.S. Patent Jul. 3, 2007 Sheet 15 0f 27 US 7,239,442 B2
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19. U.S. Patent Jul. 3, 2007 Sheet 17 0f 27 US 7,239,442 B2
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