In a relatively simple setup consisting of a microchip laser as pump source and two hydrogen-filled hollow-core photonic crystal fibers, a broad, phase-locked, purely rotational frequency comb is generated. This is achieved by producing a clean first Stokes seed pulse in a narrowband guiding photonic bandgap fiber via stimulated Raman scattering and then driving the same Raman transition resonantly with a pump and Stokes fields in a second broadband guiding kagomé-style fiber. Using a spectral interferometric technique based on sum frequency generation, we show that the comb components are phase locked.
© 2012 Optical Society of America
Fiber Optics and Optical Communications
Original Manuscript: July 19, 2012
Revised Manuscript: September 17, 2012
Manuscript Accepted: September 17, 2012
Published: October 16, 2012
A. Abdolvand, A. M. Walser, M. Ziemienczuk, T. Nguyen, and P. St. J. Russell, "Generation of a phase-locked Raman frequency comb in gas-filled hollow-core photonic crystal fiber," Opt. Lett. 37, 4362-4364 (2012)