Characterizing a fiber-based frequency comb with electro-optic modulator

TL;DR

This paper characterizes a fiber-based frequency comb with an electro-optic modulator, demonstrating noise reduction techniques and potential for generating ultra-low phase noise microwave signals.

Contribution

It provides a detailed analysis of noise sources and stabilization methods for fiber-based frequency combs with EOMs, highlighting their capabilities for low-noise microwave generation.

Findings

Low noise current supply reduces laser RIN.

Transfer functions evaluated for comb stabilization.

Potential for very low phase noise microwave signals.

Abstract

We report on the characterization of a commercial-core fiber-based frequency comb equipped with an intracavity electro-optic modulator (EOM). We investigate the relationship between the noise of the pump diode and the laser relative intensity noise (RIN) and demonstrate the use of a low noise current supply to substantially reduce the laser RIN. By measuring several transfer functions, we evaluate the potentiality of the EOM for comb repetition rate stabilization. We also evaluate the coupling to other relevant parameters of the comb. From these measureemnts, we infer the capabilities of the femtosecond laser comb to generate very low phase noise microwave signals when phase locked to a high spectral purity ultra-stable laser.