Plastic molded optical switch designed by means of optical power evaluation computer program

This paper reports a novel reflection type plastic molded optical switch which comprises two spherical prisms for totally reflecting incident light and a shutter positioned between the prisms for controlling the transmission loss of the light. The switch shows insertion loss of 9.7 dB when the switch is used in conjunction with optical fibers with 1 mm core diameter and extinction ratio of 35.1 dB. The insertion loss is lower by 8 dB than the conventional reflection type switch that employs flat reflection type prisms. In designing the switch, we evaluated the switch performance by means of a newly developed ray tracing computer program that considers optical power for each ray trace, that has not been done by the conventional evaluation technique. Discrepancy between the experimental and calculated insertion losses is +/- 1 dB. This small discrepancy confirms usefulness of our computer program.