High power all fiber mid-IR supercontinuum generation in a ZBLAN fiber pumped by a 2 μm MOPA system

Weiqiang Yang,Bin Zhang,Ke Yin,Jing Hou,Xuanfeng Zhou

doi:10.1364/oe.21.019732

Abstract

High power all fiber mid-IR supercontinuum (SC) generation in a ZBLAN fiber pumped by a 2 μm master oscillator power amplifier (MOPA) system is demonstrated. A semiconductor saturable absorber mirror (SESAM) passively mode-locked laser with pulse width of 26 ps at 1960 nm is used as the seed of the MOPA system. A laser spectrum extending from ~1.9 μm to beyond 2.6 μm is generated in a subsequent thulium-doped fiber amplifier (TDFA). Then, the spectrum is further broadened to the mid-IR region in the ZBLAN fiber. A mid-IR SC extending from 1.9 to 3.9 μm with 7.11 W average output power is obtained based on a large mode area TDFA, the SC power for wavelengths longer than 2.5 μm is 3.52 W with a power ratio of 49.5% with respect to the total SC power. The overall optical conversion efficiency from the 790 nm pump of the large mode area TDFA to the total SC output is 10.4%. To the best of our knowledge, both the 7.11 W total average power and 3.52 W average power in wavelengths beyond 2.5 μm are the highest power ever reported for a mid-IR SC generation in ZBLAN fiber pumped by 2 μm fiber lasers and TDFAs.

Highlights

Supercontinuum (SC) generation in optical fibers has attracted significant attention in the past decade owing to its usefulness in a variety of applications such as optical communication [1], frequency metrology [2], spectroscopy [3], and optical coherence tomography [4]
In this paper we demonstrate a high power all fiber mid-IR SC generation in a single mode ZBLAN fiber pumped by a 2 μm master oscillator power amplifier (MOPA) system
Similar with the small core thulium-doped fiber amplifier (TDFA) based mid-IR SC generation, the laser spectrum firstly extends in the large mode area (LMA) TDFA, in the following passive fiber, and the spectrum extends to mid-IR region in the ZBLAN fiber

Summary

Introduction

Supercontinuum (SC) generation in optical fibers has attracted significant attention in the past decade owing to its usefulness in a variety of applications such as optical communication [1], frequency metrology [2], spectroscopy [3], and optical coherence tomography [4]. M. Duhant et al reported a mid-IR SC extending up to 3.8 μm with 490 mW average output power in a ZBLAN fiber by direct pumping in the anomalous dispersion region at 2 μm [18], the power ratio of SC for wavelengths longer than 2.5 μm is 47% with respect to the total SC power, which is 1.5 times larger than that reported by [17]. In this paper we demonstrate a high power all fiber mid-IR SC generation in a single mode ZBLAN fiber pumped by a 2 μm MOPA system. In order to increase the mid-IR SC generation efficiency and further scale up the total average output power, a large mode area (LMA) TDFA and a pulse repetition rate increasing system are used. A 20 GHz sampling rate digital oscilloscope with 1.5 GHz bandwidth and an InGaAs detector with

Results and discussion

Pulse repetition rate increasing to further scale up the average output power

Conclusion