Low noise chirped pulse mode-locked laser using an intra-cavity Fabry-Pérot etalon

Abstract

This work presents an extensive investigation of the performance characteristics of a semiconductor-based Theta cavity design laser with an intra-cavity Fabry-Pérot etalon operating at 100 MHz repetition rate. The Theta laser being an external cavity harmonically mode-locked semiconductor laser exhibits supermode noise that impairs its performance. A fiberized Fabry-Pérot periodic filter inserted within the Theta laser cavity mitigates the contribution of the supermode noise to the pulse-to-pulse energy variance by 20 times. The laser has both a compressed output with picosecond pulse duration and a uniform intensity quasi-CW linearly chirped pulse output with 10 nm bandwidth. Long-term stability is attained by referencing the cavity length to the etalon using an intra-cavity Hänsch-Couillaud locking scheme.