High extinction ratio and low backreflection polarization maintaining hollow-core to solid-core fiber interconnection.

We develop a hybrid cold/heat two-step splicing approach for low loss, low backreflection, and high polarization extinction ratio (PER) hollow-core to solid-core fiber interconnection. The employed hollow-core fiber (HCF) is our recently developed high-birefringence polarization-maintaining hollow-core fiber (PM-HCF) with a PER value of ∼30 dB, and the solid-core fiber (SCF) is a commercial Panda polarization-maintaining fiber (Panda fiber). Simultaneous low backreflection (<-35 dB), low insertion loss (IL) (∼0.7 dB), and high PER (∼27 dB) are achieved, representing the first high-performance PM-HCF/SCF interconnections, to the best of our knowledge. This greatly facilitates the applications of PM-HCF in widespread fields such as precise metrologies, gyroscopes, and ultrafast/high-power laser deliveries.