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.
© 2009 Optical Society of America
Fiber Optics and Optical Communications
Original Manuscript: April 1, 2009
Revised Manuscript: July 16, 2009
Manuscript Accepted: August 11, 2009
Published: September 25, 2009
Mahmood Bagheri, Firooz Aflatouni, Alireza Imani, Ankush Goel, and Hossein Hashemi, "Semiconductor laser phase-noise cancellation using an electrical feed-forward scheme," Opt. Lett. 34, 2979-2981 (2009)