Metal-Based 1ã—2 and 1ã—4 Asymmetric Plastic Optical Fiber Couplers for Optical Code Generating Devices

Abstract

Abstract-An optical code generating device has been developed based on 1×2 and 1×4 asymmetric plastic optical fiber (POF) couplers. The code generating device provides a unique series of output power which are successively used as an optical code in a portable optical access-card system. The system is designed where the asymmetric POF coupler is embedded in an all passive portable unit. This device utilizes a tap-off ratio (TOFR) technique based on a simple variation of the tap width of an asymmetric Y-branch splitter design. A hollow-type waveguide structure is used where it eliminates the use of polymeric material for the waveguide core and allows simple fabrication and assembling of the device. The asymmetric POF coupler has been fabricated on metal-based materials using machining technique. The results for the simulated and fabricated 1×2 asymmetric couplers show the same linear characteristics between the TOFR and the tap width. The simulated devices shows a TOFR variation from 18.6% to 49.9% whereas the TOFR for the fabricated metal-based devices varies from 10.7% up to 47.7%, for a tap width of 500 µm to 1 mm. The 1 × 4 coupler designed using simple cascading of a Y-branch splitter with two 1 × 2 asymmetric couplers has been fabricated and shows similar characteristics as that of the designed 1 × 4 devices. The insertion loss for the 1 × 2 asymmetric coupler at the tap line varies from 9 dB to Corresponding author: A. A. Ehsan (aaehsan@eng.ukm.my).2 Ehsan, Shaari, and Abd Rahman 16 dB whereas for the bus line, the insertion loss is about 9 ± 0.8 dB. The insertion loss for the 1 × 4 asymmetric coupler at the output ports varies from 14 dB to 22 dB.

Optical Encryption Device for Software Protection

“…The 1x2 asymmetric coupler is a device which allows simple optical power tap. Variation of optical power can be achieved using the 1x2 asymmetric coupler using a concept known as tap-off ratio (TOFR) [13]. This design can be easily produced by changing the geometrical size of the tap line or branch as shown by Ehsan et .al.…”

Metal-Based Asymmetric Hollow Waveguide and Y-Branch Plastic Optical Fiber Couplers

“…This design is achieved by varying the size of the tap-off line or tap line. This design was part of our own work on an asymmetric POF coupler for a portable optical access-card system which was published [8]. The TOFR is given by equation (1) [7]:…”

Acrylic-based asymmetric and variable coupling ratio Y-branch plastic optical fiber coupler

“…The device reported by Suzuki et al is a Y-branch coupler with the center axis of the branching output waveguide and that of the taper waveguide shifted from each other. 11,12) In some niche applications, especially in signal measurement applications, there variable coupling ratio devices where light can be attenuated are required. The multimode device reported by Kurokawa et al uses the mirror-finished reflection at the reflecting surface of the waveguide to divide the optical power, independent of the branch corner.…”