Vernier effect within a versatile femtosecond optical parametric oscillator for broad-tunable, high-repetition-rate oscillator

TL;DR

This paper demonstrates a versatile femtosecond optical parametric oscillator utilizing the Vernier effect to achieve broad-tunable, high-repetition-rate pulses with wide bandwidth, enabling advanced applications in telecommunications and metrology.

Contribution

It introduces a simple method to generate tunable, high-repetition-rate femtosecond pulses using Vernier effect within a SPOPO by detuning the cavity FSR, avoiding complex locking systems.

Findings

Generated pulses with repetition rates from GHz to 1 THz.

Achieved 22.58 nm bandwidth supporting 160 fs pulses.

Potential for applications in high-speed data transmission and precision metrology.

Abstract

Within a synchronously pumped optical parametric oscillator (SPOPO), the inherent synchronism between the pump and the resonating signal is the magic to partly transfer the coherence property of the pump to the signal. In our demonstration, Vernier effect is observed within a femtosecond SPOPO by simply detuning the FSR of the cavity, generating signal pulses at tunable repetition rate from several GHz to 1 THz with a maximum 22.58 nm full width half maximum (FWHM) bandwidth supporting 160 fs pulses covering the C- and L-bands of the telecom wavelength region. This technique offers a simple method of active filtering of dense frequency comb lines instead of using Fabry-P\'erot (FP) cavities with complex locking system for astro-comb generation. Beside, as a promising source for frequency combs with tunable and large comb-spacing, it offers potential opportunities for applications such as high speed coherent data transmission, line-by-line pulse shaping, optical clocks and precision metrology.