Mid-infrared 1  W hollow-core fiber gas laser source

Abstract

We report the characteristics of a 1 W hollow-core fiber gas laser emitting CW in the mid-IR. Our system is based on an acetylene-filled hollow-core optical fiber guiding with low losses at both the pump and laser wavelengths and operating in the single-pass amplified spontaneous emission regime. Through systematic characterization of the pump absorption and output power dependence on gas pressure, fiber length, and pump intensity, we determine that the reduction of pump absorption at high pump flux and the degradation of gain performance at high gas pressure necessitate the use of increased gain fiber length for efficient lasing at higher powers. Low fiber attenuation is therefore key to efficient high-power laser operation. We demonstrate 1.1 W output power at a 3.1 μm wavelength by using a high-power erbium-doped fiber amplifier pump in a single-pass configuration, approximately 400 times higher CW output power than in the ring cavity previously reported.

Revolver Hollow Core Optical Fibers

“…At the same time, in a recent study [55] that was related to the gas fiber lasers based on population inversion, efficient lasing at a wavelength of 3.1 µm was demonstrated under pumping at λ p = 1.53 µm.…”

“…In most studies, gas fiber lasers are constructed in a cavity-free, single-pass scheme [5,51,[53][54][55]. Due to strong localization of light in their core (MFD~5 ÷ 50 µm) along the entire length of the fiber (~1 ÷ 10 m) active gas-filled HCFs provide a single-pass gain that is sufficient for laser radiation build-up from quantum noise.…”

“…Due to strong localization of light in their core (MFD~5 ÷ 50 µm) along the entire length of the fiber (~1 ÷ 10 m) active gas-filled HCFs provide a single-pass gain that is sufficient for laser radiation build-up from quantum noise. Thus, a single-pass scheme allows for one to realize efficient GFLs that are based on both SRS [51][52][53][54] and population inversion [55]. Designing a cavity for GFLs remains a challenging problem because there are neither fiber couplers nor analogues of fiber Bragg gratings for hollow-core fibers.…”

10 watt-level tunable narrow linewidth all-fiber amplifier

“…High-power and narrow linewidth 1.5 µm fiber lasers are required in many applications, such as coherent combination, nonlinear frequency conversion, and optical parametric oscillation. In recent years, mid-infrared fiber gas lasers have attracted intensive attention [10][11][12][13] , and the preferable pump sources are precisely tunable C-band fiber lasers with several hundreds of megahertz linewidth (matching the absorption linewidth of gas molecules such as 12 C 2 H 2 ) and at least several hundreds of mW (the usual laser threshold). To the best of our knowledge, so far there are almost no such fiber lasers having been reported.…”

“…The maximum laser power is >11 W, and the linewidth is about 200-300 MHz, which is close to the absorption linewidth of most gases at C-band. This work can provide preferable pump sources for fiber gas lasers based on hollow-core fibers [10][11][12][13] .…”