Electro-optic dual-comb interferometry over 40-nm bandwidth

TL;DR

This paper demonstrates electro-optic dual-comb interferometry across a 40-nm bandwidth in the telecommunications C band, enabling high-speed broadband measurements with potential applications in optical metrology.

Contribution

The authors achieved broadband electro-optic dual-comb interferometry over the entire C band using spectral broadening, expanding the technique's bandwidth and speed capabilities.

Findings

Measured 200 lines over 40 nm bandwidth within 10 microseconds

Achieved a signal-to-noise ratio of 100 per spectral line

Demonstrated potential for high-speed broadband optical metrology

Abstract

Dual-comb interferometry is a measurement technique that uses two laser frequency combs to retrieve complex spectra in a line-by-line basis. This technique can be implemented with electro-optic frequency combs, offering intrinsic mutual coherence, high acquisition speed and flexible repetition-rate operation. A challenge with the operation of this kind of frequency comb in dual-comb interferometry is its limited optical bandwidth. Here, we use coherent spectral broadening and demonstrate electro-optic dual-comb interferometry over the entire telecommunications C band (200 lines covering ~ 40 nm, measured within 10 microseconds at 100 signal-to-noise ratio per spectral line). These results offer new prospects for electro-optic dual-comb interferometry as a suitable technology for high-speed broadband metrology, for example in optical coherence tomography or coherent Raman microscopy.