Gain-switched laser diode seeded Yb-doped fiber amplifier delivering 11-ps pulses at repetition rates up to 40-MHz

TL;DR

This paper demonstrates the all-fiber amplification of 11-ps pulses from a gain-switched laser diode at 1063nm, achieving high peak power and energy through a multi-stage Yb-doped fiber amplifier system.

Contribution

It introduces a novel multi-stage Yb-doped fiber amplification setup for ultrashort pulses from a gain-switched laser diode, achieving high amplification and pulse quality.

Findings

Amplified pulses to 5.7 μJ energy with 11 ps duration.

Achieved peak power >0.6 MW.

Maintained low spectral and temporal broadening.

Abstract

Here, we demonstrate all-fiber direct amplification of 11 picosecond pulses from a gain-switched laser diode at 1063nm. The diode was driven at a repetition rate of 40MHz and delivered 13$\mu$W of fiber-coupled average output power. For the low output pulse energy of 0.33pJ we have designed a multi-stage core pumped preamplifier based on single clad Yb-doped fibers in order to keep the contribution of undesired amplified spontaneous emission as low as possible and to minimize temporal and spectral broadening. After the preamplifier we reduced the 40MHz repetition rate to 1MHz using a fiber coupled pulse-picker. The final amplification was done with a cladding pumped Yb-doped large mode area fiber and a subsequent Yb-doped rod-type fiber. With our setup we achieved amplification of 72dBs to an output pulse energy of 5.7$\mu$J, pulse duration of 11ps and peak power of >0.6MW.