Semiconductor laser phase-noise cancellation using an electrical feed-forward scheme.
We demonstrate the reduction of semiconductor laser phase noise by using an electrical feed-forward scheme. We have carried out proof-of-concept experiments on a commercially available distributed-feedback laser emitting at the 1550 nm communication band. The preliminary results show more than 20 times reduction in the phase-noise power spectrum. The feed-forward scheme does not have the limited bandwidth, stability, and speed issues that are common in feedback systems. Moreover, in the absence of electronic noise, feed-forward can completely cancel the close-in phase noise. In this scheme, the ultimate achievable phase noise will be limited by the electronics noise. Using the proposed feed-forward approach, the linewidth of semiconductor lasers can be reduced by 3-4 orders of magnitude in a monolithic approach using today's low-noise scaled transistors with terahertz gain-bandwidth product.
Department of Electrical Engineering-Electrophysics, University of Southern California, Los Angeles, California 90089-0271, USA.
Mahmood
M
Bagheri
Firooz
F
Aflatouni
Alireza
A
Imani
Ankush
A
Goel
Hossein
H
Hashemi