Power stable 1.5–10.5  µm cascaded mid-infrared supercontinuum laser without thulium amplifier

Abstract

We demonstrate a simple and power stable 1.5–10.5 µm cascaded mid-infrared 3 MHz supercontinuum fiber laser. To increase simplicity and decrease cost, the design of the fiber cascade is optimized so that no thulium amplifier is needed. Despite the simple design with no thulium amplifier, we demonstrate a high average output power of 86.6 mW. Stability measurements for seven days with 8–9 h operation daily revealed fluctuations in the average power with a standard deviation of only 0.43% and a power spectral density stability of ± 0.18 d B m / n m for wavelengths &lt;<!-- 10 µ m . The high-repetition-rate, robust, and cheap all-fiber design makes this source ideal for applications in spectroscopy and imaging.

Mid-infrared supercontinuum-based Fourier transform spectroscopy for plasma analysis

“…1 . The light source is a newly developed, fiber-coupled MIR SC source (DTU Fotonik, average power ~ 86 mW, pulse duration ~ 0.5 ns, repetition frequency 3 MHz 40 ). The MPC has a 31.2 m effective interaction length (Thorlabs, HC30L/M-M02) and is connected to the discharge cell, such that the reaction products of the plasma are sent to the MPC for interaction with the SC beam.…”

Recent advances in supercontinuum generation in specialty optical fibers [Invited]

“…A list of most advanced and recently developed all fiberbased MIR SC systems are reported in Table 1. In 2021, Woyessa et al demonstrated a stable and portable MIR SC laser source covering the bandwidth from 1.46-10.46 µm with an average output power of 86.6 mW and a repetition rate of 3 MHz in a fiber cascade comprising of silica, ZBLAN, and chalcogenide fibers pumped by 0.5 ns pulsed Er/Yb-master oscillator power amplifier (MOPA) without any amplifier stages [81]. Yan et al demonstrated a watt-level (1.13 W) MIR SC spanning from 2-6.5 µm in a butt coupled ZBLAN and As 2 S 3 cascaded fiber system pumped by a 1550 nm pulsed distributed feedback laser and few stages of thulium-doped fiber amplifier [82].…”

Mid-infrared supercontinuum generation in chalcogenide glass fibers: a brief review

“…Generally, fluoride fibers are always chosen as the firststage fiber in the cascading scheme because of the following excellent properties: 1) high damage threshold; 2) generating SC sources with > 3.5 μm long wavelength edge extending above the ZDW of typical step-index fluoride fibers around 1.5 μm; 3) high output power of up to 30 W [18]. Subsequently, this concept has been proved to be feasible by many experimental results [29,[76][77][78][79][80]. In [29], a MOPA pump laser with a repetition rate of 600 kHz shown in Fig.…”

“…In order to reduce the system complexity and maintain the SC output power close to hundred mW level at the same time, a configuration of the cascading SC source without thulium amplifier is employed and shown in Fig. 14a, where a section of passive Tm and Ge/Tm co-doped fibers were used between the silica fiber and ZBLAN fiber to redistribute the pump power above 2 μm [79]. After the cascaded three stage fibers, the output spectrum of the SC source spans 1.46-10.46 μm with an average output power of 86.6 mW.…”