Abstract
We propose and demonstrate an in-band optical signal-to-noise ratio
(OSNR) monitoring technique using the output power ratio (PR) of the nonlinear
optical loop mirror (NOLM) theoretically and experimentally. Operation point
(OP) is investigated to be the input average power which corresponds to the
first maximum of the power ratio curve. The monitoring performances using
PR are proved to be better than those just using one output port of NOLM for
on-off keying (OOK) and differential phase-shift-keying (DPSK) signals with
different duty cycles: non-return-to-zero (NRZ), carrier-suppressed return-to
zero (CSRZ), return-to-zero (RZ) with 50% and 33% duty cycle (RZ 50 and RZ
33) at 40 Gb/s. For 80 Gb/s RZ-differential quadrature phase-shift keying
(DQPSK) signal, we obtained 12.16 dB maximum power variation
and 13–39.8 dB monitoring range experimentally. The power ratio scheme
can improve the contrast ratio by 7.05 dB and the monitoring range by 13.8
dB compared with that just using the transmission port. The tolerance to residual
chromatic dispersion of the monitoring performance is investigated to be less
than 1.7 ps/nm. The experimental validations are consistent with the theoretical
analyses. The proposed scheme can be used in ultra-speed transmission systems.
© 2012 IEEE
PDF Article
More Like This
Cited By
You do not have subscription access to this journal. Cited by links are available to subscribers only. You may subscribe either as an Optica member, or as an authorized user of your institution.
Contact your librarian or system administrator
or
Login to access Optica Member Subscription