Abstract
We demonstrate, to the best of our knowledge, the first carrier-envelope offset (CEO) frequency stabilization of a GHz femtosecond laser based on opto-optical modulation (OOM) of a semiconductor saturable absorber mirror (SESAM). The 1.05-GHz laser is based on a Yb:CALGO gain crystal and emits sub-100-fs pulses with 2.1-W average power at a center wavelength of 1055 nm. The SESAM plays two key roles: it starts and stabilizes the mode-locking operation and is simultaneously used as an actuator to control the CEO frequency. This second functionality is implemented by pumping the SESAM with a continuous-wave 980-nm laser diode in order to slightly modify its nonlinear reflectivity. We use the standard -to- method for detection of the CEO frequency, which is stabilized by applying a feedback signal to the current of the SESAM pump diode. We compare the SESAM-OOM stabilization with the traditional method of gain modulation via control of the pump power of the Yb:CALGO gain crystal. While the bandwidth for gain modulation is intrinsically limited to by the laser cavity dynamics, we show that the OOM provides a feedback bandwidth above 500 kHz. Hence, we were able to obtain a residual integrated phase noise of 430 mrad for the stabilized CEO beat, which represents an improvement of more than 30% compared to gain modulation stabilization.
© 2017 Optical Society of America
Full Article | PDF ArticleMore Like This
Martin Hoffmann, Stéphane Schilt, and Thomas Südmeyer
Opt. Express 21(24) 30054-30064 (2013)
Kutan Gürel, Valentin J. Wittwer, Sargis Hakobyan, Stéphane Schilt, and Thomas Südmeyer
Opt. Lett. 42(6) 1035-1038 (2017)
Daniel I. Herman, Jean-Daniel Deschênes, Henry Timmers, Ian Coddington, and Nathan R. Newbury
Opt. Express 30(21) 38684-38694 (2022)