Fully self-referenced frequency comb consuming 5 Watts of electrical power

TL;DR

This paper introduces a low-power, fully self-referenced 100-MHz frequency comb using a hybrid fiber/waveguide design, achieving stable operation with less than 5 W of electrical power through innovative temperature control and supercontinuum generation.

Contribution

The work demonstrates a novel low-power frequency comb design that integrates supercontinuum generation in silicon nitride waveguides with efficient temperature stabilization, significantly reducing power consumption compared to traditional systems.

Findings

Achieved self-referenced frequency comb with <5 W power consumption.

Implemented temperature tuning with a small thermal mass, enabling rapid stabilization.

Reduced power requirements for supercontinuum generation and stabilization.

Abstract

We present a hybrid fiber/waveguide design for a 100-MHz frequency comb that is fully self-referenced and temperature controlled with less than 5 W of electrical power. Self-referencing is achieved by supercontinuum generation in a silicon nitride waveguide, which requires much lower pulse energies (~200 pJ) than with highly nonlinear fiber. These low-energy pulses are achieved with an erbium fiber oscillator/amplifier pumped by two 250-mW passively-cooled pump diodes that consume less than 5 W of electrical power. The temperature tuning of the oscillator, necessary to stabilize the repetition rate in the presence of environmental temperature changes, is achieved by resistive heating of a section of gold-palladium-coated fiber within the laser cavity. By heating only the small thermal mass of the fiber, the repetition rate is tuned over 4.2 kHz (corresponding to an effective temperature change of 4.2 {\deg}C) with a fast time constant of 0.5 s, at a low power consumption of 0.077 W/{\deg}C, compared to 2.5 W/{\deg}C in the conventional 200-MHz comb design.