Low loss nested hollow-core anti-resonant fiber at 2 µm spectral range

Abstract

We report the fabrication and characterization of a five-tube nested hollow-core anti-resonant fiber (Nested HC-ARF), which exhibits outstanding optical performance in terms of a record attenuation value of 0.85 dB/km at 2 µm wavelength range with a 200 nm bandwidth below 2 dB/km and excellent modal purity. The power handling capability of the Nested HC-ARF is also demonstrated in this work. Pulses of 75 W, 160 ps from the thulium-doped fiber laser are delivered using a 6-m-long fabricated Nested HC-ARF. The tested fiber is coiled into a 20 cm bending radius and achieves a coupling efficiency of 86.7%. The maximum average power of 60.5 W is transmitted through our Nested HC-ARF in a robust single-mode fashion without introducing any damage to the input and output fiber end-faces, which demonstrates the superior ability of such a fiber for high-power laser delivery.

Polarization Purity and Dispersion Characteristics of Nested Antiresonant Nodeless Hollow-Core Optical Fiber at Near- and Mid-IR Wavelengths for Quantum Communications

“…hollow-core photonic bandgap fibers (HC-PBGFs) with reported attenuation of 2.5 dB/km at 2 𝜇m [24]. The measured attenuation is also close to the record attenuation value of 0.85 dB/km achieved in a five-tube NANF [25].…”

Hollow-Core Optical Fibers for Telecommunications and Data Transmission

“…Fused silica NANF with low loss, 0.85-1.25 dB/km in several bands close to 2 µm (≈1980 nm, ≈2040 nm, ≈2100 nm), was also reported by researchers from the Beijing University of Technology in China in 2021 [56]. This fiber was designed for optical power delivery, with a large core diameter (46 µm) and cladding made of five nested tubes.…”

Design of 2 μm Low-Loss Hollow-Core Anti-Resonant Fibers

“…Therefore, the fine mesh sizes of λ/4 and λ/6 were used in the sections of air and silica, respectively [ 9 ]. To ensure the convergence of the numerical results, the code was tested by reproducing the results in [ 22 , 25 ].…”

“…For HC-ARF, because the contact surface between the core and the cladding quartz wall is small, and the core diameter size is large, the light field intensity is weak at the intersection, and the SSL can be reduced by an order of magnitude [ 9 , 14 ]. To control the modal content and attenuation coefficient, HC-ARF nested with several types of anti-resonant tubes has been proposed, studied, and manufactured, including circular anti-resonant tubes [ 4 , 10 , 16 , 17 , 18 , 19 ], “ice cream cone”-shaped anti-resonant tubes [ 19 , 20 ], elliptical anti-resonant tubes [ 21 ], nested anti-resonant tubes [ 5 , 9 , 11 , 22 ], and more complex shaped anti-resonant tubes [ 23 ]. In addition, HC-ARF has become one of the research hotspots in the field of optical fibers due to its advantages, such as ultrawide transmission bandwidth, low confinement loss, and relatively simple preparation.…”

“…In addition, HC-ARF has become one of the research hotspots in the field of optical fibers due to its advantages, such as ultrawide transmission bandwidth, low confinement loss, and relatively simple preparation. In 2022, Xin Zhang et al [ 22 ] reported the preparation and characterization of a nested five-tube HC-ARF with an attenuation rate of 0.85 dB/km at 2 μm. The bandwidth was 200 nm with a confinement loss below 2 dB/km, and the HC-ARF showed excellent modal purity.…”