Amplification of arbitrary frequency chirps of pulsed light on nanosecond timescales

TL;DR

This paper presents a system that amplifies arbitrarily shaped frequency-chirped pulses of light at 780 nm on nanosecond timescales, achieving high chirp rates and peak powers through fiber modulators, amplifiers, and clever power management.

Contribution

It introduces a novel setup combining fiber phase modulators, amplifiers, and multiplexing techniques to generate high-power, arbitrarily shaped frequency chirps on nanosecond timescales.

Findings

Achieved chirp rates exceeding 3 GHz/10 ns.

Generated peak powers greater than 1 W.

Enabled arbitrary chirp shapes with waveform control.

Abstract

We have developed a system for producing amplified pulses of frequency-chirped light at 780 nm on nanosecond timescales. The system starts with tunable cw laser light and employs a pair of fiber-based phase modulators, a semiconductor optical amplifier, and a tapered amplifier to achieve chirp rates exceeding 3 GHz/10 ns and peak powers greater than 1 W. Driving the modulators with an arbitrary waveform generator enables arbitrary chirp shapes, such as two-frequency linear chirps. We overcome the optical power limitations of the modulators by duty cycling and avoid unseeded operation of the tapered amplifier by multiplexing the chirped pulses with "dummy" light from a separate diode laser.