Direct photolithography on optical fiber

Photolithography is cost-effective and has been used for fabricating planar semiconductor devices. However, it cannot be applied to optical fiber for obtaining complicated microstructures. The first and biggest problem for realizing photolithography on an optical fiber is the resist coating on the non-planar surface. When spin coating is used, the resist becomes too uneven in thickness to use for the patterning. The concave and convex regions make the resist thickness vary due to the surface tension. A resist spraying system is developed for three-dimensional photolithography. The photoresist is sprayed as minute particles on the sample surface making a uniform resist film without suffering problems due to surface tension. New process techniques are developed and applied to direct photolithography on single mode optical fiber.