Optical communications – Transmitter – Having particular modulation
Reexamination Certificate
2007-08-14
2007-08-14
Li, Shi K. (Department: 2613)
Optical communications
Transmitter
Having particular modulation
C398S186000
Reexamination Certificate
active
10378096
ABSTRACT:
A duobinary optical communication system is disclosed that employs pulse amplitude modulation (PAM) techniques to provide further improvements in spectral efficiency. A disclosed PAM duobinary optical transmitter converts a plurality of input bits to an N level signal using PAM techniques; adds a current N level signal to a previous N level signal to produce a 2N−1 level signal; and converts the 2N−1 level signal to an optical signal for transmission to a receiver. A disclosed PAM duobinary optical receiver detects a power level of the received optical signal (encoded using pulse amplitude modulation and duobinary encoding techniques to encode a plurality of bits) and maps the detected power level to a plurality of bits to return the transmitted information. An exemplary PAM-4 duobinary optical communication system combines PAM-4 modulation techniques with duobinary pulse shaping techniques to provide an overall factor of four improvement in spectral efficiency by reducing the bandwidth of the optical signal.
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Azadet Kameran
Saibi Fadi Ryad Olivier
Agere Systems Inc.
Li Shi K.
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