Comb-assisted coherence transfer between laser fields

TL;DR

This paper demonstrates a method to transfer phase coherence between laser fields over large frequency gaps using electro-optic modulation and optical combs, enabling precise laser field shaping.

Contribution

It introduces a novel technique for long-distance phase transfer between laser fields via electro-optic devices and optical combs, expanding capabilities in laser coherence control.

Findings

Successful phase transfer over large frequency gaps

Use of fibered Mach-Zehnder modulator for cloning

Potential for improved laser coherence management

Abstract

Single mode laser fields oscillate at frequencies well outside the realm of electronics, but their phase/frequency fluctuations fall into the radio frequency domain, where direct manipulation is possible. Electro-optic devices have sufficient bandwidth for controlling and tailoring the dynamics of a laser field down to sub-nanosecond time scales. Thus, a laser field can be arbitrarily reshaped and in particular its phase/frequency fluctuations can be in principle removed. In practice, the time evolution of a reference laser field can be cloned to replace the fluctuations of another laser field, at a close-by frequency. In fact, it is possible to exploit a partially stabilized optical comb to perform the cloning across a large frequency gap. We realize this long-haul phase transfer by using a fibered Mach-Zehnder single-sideband modulator driven by an appropriate mix of the beat notes of the master and the slave laser with the comb.