In the field of photonics, there is an increasing need to couple arrays of optical fibers with arrays of receivers or transmitters. One method of doing this is by using micro-lens arrays on the same pitch as the active devices. This paper addresses the important concerns of focal point center-to-center accuracy and the coupling efficiency of these micro-lenses using computer image analysis. Although the image processing techniques used are conventional, their application to micro-lens testing presents a novel approach to determining manufacturing accuracy and lens coupling efficiency. Data on the behavior of the micro-lens can be gathered using the micro-lens array to image a laser beam through a relay lens and onto a CCD camera detector. This paper presents some preliminary experimental results and describes the algorithms that perform the following functions: (1) Using standard Ronchi rulings, calculate image scale and determine if geometric distortion caused by the relay lens is present in image data. (2) Find focal spots of multiple lenses in an image using region aggregation via recursive connectivity evaluation providing sub-pixel moment calculation. (3) Calculate lens coupling efficiency by summing the intensities of all pixels composing the focus spots and comparing them with similar data representing the light incident on the first surface of the lens.

Date Published: 1 January 1992
PDF: 11 pages
Proc. SPIE 1531, Advanced Optical Manufacturing and Testing II, (1 January 1992); doi: 10.1117/12.134850

Published in SPIE Proceedings Vol. 1531:
Advanced Optical Manufacturing and Testing II
Victor J. Doherty, Editor(s)