Phase noise suppression for a high-power optical frequency comb

Abstract

We demonstrate a high-power frequency comb consisting of a Ti:sapphire bulk seed laser and a large-mode-area Yb-fiber power amplifier. An all-fiber pulse stretcher was carefully designed to suppress the amplitude-to-phase noise in the fiber amplifier. Near-Fourier-limited pulses were obtained with an average power of up to 30 W and a pulse duration of 178 fs. The free-running carrier-envelope-phase frequency was optimized to have a linewidth of 52 kHz, which was further phase-locked to a narrow linewidth of 1.8 mHz with an integrated phase noise of 0.78 rad.

Pump-induced carrier envelope offset frequency dynamics and stabilization of an Yb-doped fiber frequency comb

“…Solid-state bulk lasers such as Ti:sapphire and Yb-doped crystal typically require critical bulk optical design and alignment. [4][5][6] Rare-earthdoped (such as Er 3+ , Yb 3+ , and Tm 3+ dopants) fiber lasers are attractive since laser pulses are well-confined in the fiber waveguides so that they are extremely robust even under significant vibration. [7,8] In various existing technologies, the Ybfiber frequency comb has attracted considerable interests for its low-cost direct diode pump, inherent robustness of fiber system, and suitability for high-power amplification.…”