Fabrication of antireflective subwavelength-grating structures on optical fiber end faces using UV nanoimprinting technique

Antireflective coatings at the tips of optical fibers are essential optical components to couple efficiently light with the optical fibers. We proposed optical fibers with antireflective subwavelength gratings (SWGs) and their fabrication method using an ultraviolet (UV) nanoimprinting technique. We developed a dedicated UV nanoimprinting machine to press the tip of an optical fiber to a mold. Using the developed machine, antireflective SWGs with the period of 270nm were fabricated at the tips of optical fibers. A nickel SWG with 270nm period and 400±50nm height was used as a mold. Reflectance and transmittance from the optical fiber tip with the SWG were measured and compared with that without the SWG.