Fabrication of 1 x 2 Asymmetric Plastic Optical Fiber Coupler for Portable Optical Access-Card System

An optical code generating device using plastic optical fiber (POF) coupler for a portable optical access card system is presented. The code generating device has been constructed using asymmetric hollow POF coupler design. The device provides a unique series of output light intensities which are successively used as an optical code. Ray tracing models of various coupler designs showed a linear relationship between the tap-off ratio (TOFR) and the waveguide tap width. The asymmetric POF coupler has been fabricated on metal-based materials using machining technique. The results for the simulated and fabricated metal-based 1 x 2 asymmetric couplers show the same linear characteristics between the TOFR and the tap width. The simulated devices show a TOFR variation from 18.6 to 49.9% whereas the TOFR for the fabricated metal-based devices varies from 10.7 to 47.7%, for a tap width of 500 mu m to 1 mm. The insertion loss for the 1 x 2 asymmetric coupler at the tap line varies from 12.7 to 21.2 dB whereas for the bus line, the average insertion loss is about 12 dB. (C) 2011 The Japan Society of Applied Physics