Title:
METHOD AND APPARATUS FOR IMPROVING SPECTRAL EFFICIENCY IN WAVELENGTH DIVISION MULTIPLEXED TRANSMISSION SYSTEMS
Document Type and Number:
WIPO Patent Application WO1999044298
Kind Code:
A3
Abstract:
A method and apparatus (Fig. 3) is provided for transmitting an optical signal. The method includes the step of generating an optical signal that includes a plurality of optical channels, which are sequentially numbered from 1 to N from lowest to highest wavelength. A state-of-polarization of predetermined odd-numbered channels (TRANS. #1,#3,#N-1) is oriented to be substantially orthogonal to a state of polarization of predetermined even-numbered channels (TRANS. #2,#4,#N) by directing the predetermined odd-numbered channels and the predetermined even-numbered channels through orthogonally polarizing inputs of a polarization coupler (315). The odd-numbered channels and the even-numbered channels may be directed through first and second wavelength combiners (307-308), respectively, prior to orienting their states of polarization. The orthogonal relationship between the states of polarization of odd and even-numbered channels advantageously limits the four-wave mixing products that can be generated in the optical transmitter and the optical transmission path to which it is typically coupled.
Inventors:
BERGANO NEAL S
DAVIDSON CARL R
DAVIDSON CARL R
Application Number:
PCT/US1999/004327
Publication Date:
November 04, 1999
Filing Date:
February 26, 1999
Export Citation:
Assignee:
TYCO SUBMARINE SYSTEMS LTD (US)
International Classes:
H04B10/2507; H04B10/2563; H04B10/50; H04B10/532; H04J14/02; H04J14/06; (IPC1-7): H04J14/06
Foreign References:
| US5841557A | 1998-11-24 |
Other References:
See also references of EP 1060589A4
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