Chirp-grating lens for guided-wave optics

Abstract
A high-throughput diffraction-limited chirp-grating Bragg diffraction lens for guided-wave optical device applications has been demonstrated with planar photolithographic fabrication techniques. Diffraction-limited performance has been obtained with a 2-mm-aperture f/16 lens focusing the He-Ne laser beam to a 6.1-μm spot size. The grating diffraction efficiency to the focus is over 90%. This type of lens has predictable focusing properties which are insensitive to process variations, an important consideration for accurately aligned integrated optical systems.