Self-referenced characterization of optical frequency combs and arbitrary waveforms using a simple, linear, zero-delay implementation of spectral shearing interferometry

TL;DR

This paper presents a simple, linear, zero-delay spectral shearing interferometry method for characterizing optical frequency combs and waveforms, demonstrating high sensitivity and self-referenced dispersion measurements.

Contribution

The authors introduce a novel, easy-to-implement spectral shearing interferometry technique that works at very low power levels and enables self-referenced dispersion analysis.

Findings

Successfully characterized 10 GHz frequency combs generated by phase modulation.

Achieved measurement sensitivity down to 100 nW average power.

Demonstrated self-referenced dispersion measurement over 25 km of fiber.

Abstract

We discuss a simple, linear, zero-delay implementation of spectral shearing interferometry for amplitude and phase characterization of optical frequency comb sources and arbitrary waveforms. We demonstrate this technique by characterizing two different high repetition rate (~10 GHz) frequency comb sources, generated respectively by strong external and intracavity phase modulation of a continuous-wave laser. This technique is easy to implement, requiring only an intensity modulator and an optical spectrum analyzer (OSA), and is demonstrated to work at average power levels down to 100nW (10aJ/pulse at 10 GHz). By exploiting the long coherence lengths of these frequency combs and the self-referenced nature of the measurement, we also demonstrate a simple single-ended measurement of dispersion and dispersion slope in long lengths of fiber (>25km).