Influence of Thermo-Mechanical Mismatch when Nanoimprinting Anti-Reflective Structures onto Small-core Mid-IR Chalcogenide Fibers

Thermal nanoimprinting of anti-reflective (AR) structures onto optical fiber end-faces is a practical and versatile method for increasing the throughput of chalcogenide fiber-based systems and light sources [1] - [3]. The high refractive indices of chalcogenide glasses cause reflections at interfaces with air or other materials on the order of 20 % per interface, which not only limits the throughput of the system, but may also cause parasitic amplification and adversely affect sensitive optical components. Compared with AR thin film coatings, nanoimprinting does not suffer from issues with coating adhesion and bandwidth limits, and does not require clean room conditions nor specialized deposition equipment. Due to the low glass transition temperature (T g ) of chalcogenide glasses, nanoimprinting can be performed using simple hotplates operating at around 200-300 °C.