Ultra-low fusion splicing loss between silica and ZBLAN fiber for all-fiber structured high-power mid-infrared supercontinuum generation

Abstract The improvement of mid-infrared supercontinuum (MIR-SC) power, spectrum width, and flatness had been drastically limited by the coupling inefficiency between silica and soft-glass fibers. In this work, the achievement of a fusion splicing between single-mode silica and ZBLAN fiber with ultra-high coupling efficiency, high robustness, and low thermal instability has been explored and demonstrated by using the asymmetric fiber splicing technology. By tuning power and splicing offset finely, a high-quality fusion-splicing point is achieved with the splicing loss of less than 0.1 dB. In addition, a long-term stable 5.89 W MIR-SC with spectral bandwidth covering from 2 μm to 3.8 μm, which shows that the stability and robustness of this splicing point are high enough for any practical applications, is demonstrated for experimental verification. This work will lay a solid foundation for the further development of high-quality all-fiber structured MIR-SC.