United States Patent [191
[11]
[45]
Cimini, Jr. et a1.
TECHNIQUE FOR COHERENT OPTICAL
COMMUNICATION
Apr. 16, 1991
Y. Kodoh et al., “Polarization Control on Output of
Single-Mode Optical Fibers”, IEEE J. Quant. Elec
tron., vol. QE-l7, No. 6, pp. 991-994.
H. C. Lefevre, “Single-Mode Fibre Fractional Wave
[75] Inventors: Leonard J. Cimini, Jr., Howell; Isam
M. I. Habbab, Old Bridge, both of
NJ.
Devices and Polarisation Controllers”, Electron. Lett.,
vol. 16, N0. 20, Sep. 25, 1980, pp. 778-780.
T. Imai et al., “Optical Polarisation Control Utilising an
[73] Assignee: AT&T Bell Laboratories, Murray
Hill, NJ.
Optical Heterodyne Detection Scheme”, Electron.
[21] App]. No.: 308,697
[63]
5,008,958
on Single-Mode Optical Fibers”, Electron. Lett., vol.
16, No. 15, Jul. 17, 1980, p. 573.
[54] POLARIZATION-INSENSITIVE
[22] Filed:
Patent Number:
Date of Patent:
Lett., vol. 21, Jan. 17, 1985, pp. 52-53.
(List continued on next page.)
Primary Examiner-Reinhard J. Eisenzopf
Feb. 8, 1989
Related US. Application Data
Continuation-in-part of Ser. No. 145,446, Jan. 19, 1988,
Assistant Examiner—L. Van Beek
abandoned, and a continuation-in-part of Ser. No.
[57]
ABSTRACT
To exploit the potential advantages of coherent optical
Attorney, Agent, or Firm—Samuel H. Dworetsky
145,358, Jan. 19, 1988, abandoned.
communications systems, the polarization states of the
received optical signal and the local oscillator waves
must be matched. A mismatch may severely degrade
[51]
Int. Cl.5 ........................................... .. H04B 10/06
[52]
US. Cl. .................................. .. 455/619; 455/608;
[58]
Field of Search ............. .. 455/619, 616, 600, 606,
[56]
455/607, 608; 307/1, 3, 2
References Cited
cause the received signal state of polarization changes
with time and along the ?ber. We ?rst review several
PUBLICATIONS
l. P. Karninow, “Polarization in Optical Fibers”, IEEE
J. Quant. Electron, vol. QE-l7, No. 1, Jan. 1981, pp.
15-22.
T. Okoshi, “Recent Advances in Coherent Optical
sitive technique reduces the problem of polarization
mismatch by forcing the polarization state of either the
455/616
’ detection performance. These mismatches occur be
existing techniques for handling this problem, such as
polarization-maintaining ?bers, polarization-state con
trollers and polarization-diversity receivers. The insen
transmitted signal or local oscillatorvto vary with time
Fiber Communication Systems”, J. Lightwave Tech.,
in a non-adaptive manner so that polarization-insensi
vol. LT-S, No. 1, Jan. 1987, pp. 44-52.
adopts a completely new approach which uses high
tive performance is obtained. The proposed scheme
I. P. Kaminow, “Polarization Maintaining Fibers”, Ap
plied Scienti?c Research, vol. 41, 1984, pp. 257-270.
J. Noda et al., “Polarization-Maintaining Fibers and
birefringence single-mode ?bers to implement polariza
tion switching. These techniques require only a single
Their Applications”, J. Lightwave Tech., vol. LT-4,
mance, with a power penalty relative to ideal of 3 dB. A
photodetector and give a ?xed level of detection perfor
No. 8, Aug. 1986, pp. 1071-1089.
speci?c technique is presented in which polarization
M. Monierie, “Polarization-Maintaining Single-Mode
insensitive heterodyne detection is achieved through
Fiber Cables: In?uence of Joins”, App. Optics, vol. 20,
No. 14, Jul. 1981, pp. 2400-2406.
data-induced polarization switching. The polarization
-
switching is brought about by inserting a passive, bire
fringent optical device in the path of the transmitted
F SK signal.
R. Ulrich, “Polarization Stabilization on Single-Mode
Fiber”, App. Phys. Lett., vol. 35, No. 11, Dec. 1979, pp.
840-842.
M. Kubota et a1., “Electro-Optical Polarisation Control
A as
6 Claims, 24 Drawing Sheets
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L. J. Cimini, Jr., “Analysis and Simulation of a Digital
OTHER PUBLICATIONS
T. Okoshi et al., “New Polarisation-Control Scheme
Mobile Channel Using Orthogonal Frequency Division
Multiplexing”, IEEE Trans. Commun., vol. COM-33,
for Optical Heterodyne Receiver Using Two Faraday
No. 7, Jul. 1985, pp. 665-675.
R. C. Alferness et al., “Electro-Optic Waveguide
1985, pp. 787-788.
TE-TM Mode Converter with Low Drive Voltage”,
T. Okoshi et al., “A New Polarisation-State Control ' Optics Lett., vol. 5, No. 11, Nov. 1980, pp. 473-475.
Device: Rotatable Fiber Cranks”, Electron. Lett., vol. R. C. Alferness, “Electrooptic Guided-Wave Device
21, No. 20, Sep. 26, 1985, pp. 895-896.
for General Polarization Transformations”, IEEE J.
T. Okoshi, “Polarisation-State Control Schemes for Quant. Electron, vol. QE-17, No. 6, Jun. 1981, pp.
Rotators”, Electron. Lett., vol. 21, No. 18, Aug. 29,
Heterodyne or Homodyne Optical Fiber Communica
tions”, J. Lightwave Tech., vol. LT-3, No. 6, Dec.
1985, pp. 1232-1237.
965-969.
‘
R. C. Alfemess et al., “High-Speed Waveguide Elec
tro-Optic Polarization Modulator”, Optics Lett., vol. 7,
T. Okoshi, “Heterodyne-Type Optical Fiber_Commu
No. 10, Oct. 1982, pp. 500-502.
R. C. Alferness et al., “Low Loss, Wavelength Tunable,
nications”, IOOC ’81, San Francisco, Apr. 1981, p. 44.
T. Okoshi, “Polarization-Diversity Receiver for
Heterodyne/Coherent Optical Fiber Communica
Waveguide Electro-Optic Polarization Control for
A: 1.32 pm”, App. Physics Lett., vol. 47, No. 11, Dec.
tions”, IOOC ’83, Jun. 1983, pp. 386-387.
T. G. Hodgkinson et al., “Demodulation of Optical
D. G. Carlson et al., “Intracavity Electrooptic Fre
1985, pp. 1137-1139. -
DPSK Using In-Phase and Quadrature Detection”,
Electron Lett., vol. 21, No. 19, Sep. 12, 1985, pp.
quency Tuning Polarization Switching and Q-Switch
ing of a NdzYAG Laser Oscillator”, IEEE J. Quant.
Electron, vol. QE-4, No. 3, Mar. 1968, pp. 93-98.
S. T. Hendow et al., “Observation of Bistable Behavior
in the Polarization of a Laser”, Optics Lett., vol. 7, No.
867-868.
B. Glance, “Polarization Independent Coherent Optical
Receiver”, J. Lightwave Tech., vol. LT-5, No. 2, Feb.
1987, pp. 274-276.
8, Aug. 1982, pp- 356-358.
H. L. Van Trees, Detection, Estimation and Modula Y. C. Chen et al., “Polarization Bistability in Sernicon
tion Theory, Part I, John Wiley, 1968, pp. 335-348.
‘ ductor Lasers”, App. Phy. Lett., vol. 46, No. 1, Jan.
D. Kreit et al.,_ “Polarization-Insensitive Optical Het
_
' 1985, pp. 356-358.
erodyne Receiver for Coherent FSK Communrca- .
tions”, Electron. Lett., vol. 23, No. 4, Feb. 12, 1987, pp.
168-169.
A. J. Noda et al., “Single-Mode Fiber Devices”, Opto
electronics-Devices and Technologies, vol. 1, No. 2,
Dec. 1986, pp. 175-194.
T. G. Hodgkinson et al., “Polarisation Insensitive Het
1
E
L
5
S. E. Harris et al., “Optical Network Synthesis Using
Birefringent Crystals”, IEEE Proc., vol. 52, No. 4, Apr.
1964, pp- 411-412.
S. E. Harris, “Dernodulation of Phase-Modulated Light
Using Birefringent Crystals”, IEEE Proc., vol. 52, No.
7, Jul. 1964, pp. 823-831.
R. Ulrich et al., “Polarization Optics of Twisted Sin
erodyne Detection Using Polarisation Scrambling”, gle-Mode Fibers”, App. Optics, vol. 18, No. 13, Jul.
Electron. Lett., vol. 23, No. 10, May 7, 1987, pp. 1979, pp. 2241-2251.
513-514.
M. Ross, Laser Receivers, Wiley, 1966, pp. 244-250.
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