Optical communications – Transmitter – Having particular modulation
Reexamination Certificate
2008-07-01
2008-07-01
Chan, Jason (Department: 2613)
Optical communications
Transmitter
Having particular modulation
C398S037000, C398S185000, C398S186000, C398S188000, C398S198000
Reexamination Certificate
active
07394992
ABSTRACT:
In an optical transmitter, continuous wave light from a laser passes through a data modulator (DM) for non-return-to-zero (NRZ) encoding of a data stream and through a pulse modulator to add return-to-zero encoding to the modulated optical signal. A modulator controller monitors the output optical signal power, optimizes the bias setting for the DM and the PM, and optimizes the phase relationship between the pulse and data components of the modulated optical signal. For each optimization, a low amplitude and low frequency dither signal is injected at appropriate points in the modulator. A single photo detector and electrical receiver are used in a multiplexed fashion to monitor the optical output signal and derive separate feedback signals. Remaining control circuitry forces a null in a respective residual dither component in the optical output signal to maintain the desired bias level or phase alignment.
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Fjelde Tina
Kaufmann John E.
Kimmitt Myles
Mamyshev Pavel V.
Mikkelsen Benny P.
Chan Jason
Leung Danny W
Mintera Corporation
Weingarten Schurgin, Gagnebin & Lebovici LLP
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