Abstract

A waveguide lens is a key component for integrated optics. Extensive work in glass and LiNbO₃ materials has been reported on the subject. However, a semiconductor material such as InP is more advantageous for optical-communications applications because both passive and active (lasers, amplifiers, detectors) components working at 1.55 µm can be integrated on the same chip. Although some work has been reported in GaAs,^1,2 very little has been published for InP. A practical lens for photonic integrated circuits (PIC’s) should collimate (focus) the light originating from (coupling into) a waveguide. Typically, this requires an aperture of at least f/5 to accommodate the divergence of the output light from a waveguide, and it requires a focused spot size of a few micrometers to optimize coupling into a fiber or a waveguide. Insertion loss should also be kept low. Here, we report an integrated lens formed by two aspheric surfaces that meets these requirements and uses a simple wet- etch processing technique.

© 1993 Optical Society of America