Long-term optical phase-coherent two-color femtosecond pulses were generated by use of passively timing-synchronized Ti:sapphire and Cr:forsterite lasers. The relative carrier-envelope phase relation was fixed by an active feedback loop. The accumulated phase noise from 10 mHz to 1 MHz of the locked beat note was 0.43 rad, showing tight phase locking. The optical frequency fluctuation between two femtosecond combs was submillihertz, with a 1 s averaged counter measurement over 3400 s, leading to a long-term femtosecond frequency-comb connection.
© 2005 Optical Society of America
Yohei Kobayashi, Dai Yoshitomi, Masayuki Kakehata, Hideyuki Takada, and Kenji Torizuka, "Long-term optical phase locking between femtosecond Ti:sapphire and Cr:forsterite lasers," Opt. Lett. 30, 2496-2498 (2005)