Chalcogenide-glass microlenses attached to optical-fiber end surfaces

Convex microlenses of As(2)S(3) glass have been fabricated on oxide-glass fiber ends by use of a photolithographic technique. As(2)S(3) film evaporated on the end surface of an optical fiber is exposed to light through the opposite end surface, and the film etching is observed under a microscope. This process produces a lens that is automatically positioned on the fiber core. The As(2)S(3) film possesses a high refractive index, which is favorable for production of microlenses with short focal lengths of ~10 mum.