Design and implementation of pluggable optical backplane system with flexible polymeric waveguide.

Abstract

General problems with the electrical interconnections for high-speed transmission systems include electromagnetic interference and compatibility (EMI/EMC), low data throughput, crosstalk, and high power consumption. To overcome the bottlenecks of electrical interconnections, new architectures for the optical backplane system that use optical waveguides as a transmission medium, are needed. To implement an optical backplane system, a pluggable optical board interconnection is proposed in order to minimize both loss and cost. The direct coupling of an optical waveguide between boards can be realized by using a plug-adaptor structure. Due to the reduced use of micro-optics in direct coupling mechanisms, both a low loss and a low packaging cost can be made possible. For the implementation of an optical backplane system with a pluggable coupling structure, a flexible polymeric optical waveguide that would serve as a transmission medium was fabricated by a hot embossing process. The transmitter/receiver board and the optical backplane board were fabricated by a conventional lamination process. The optical plug-adapter structure for the inter-board optical interconnection was designed for direct coupling. In the proposed optical backplane system that uses a flexible polymeric optical waveguide, the coupling structure for the board-to-board interconnection was designed to be connected with two guide pins and the holes of the optical plug-adaptor. To provide a change in the optical path on the backplane board, the flexible optical waveguide was bent at an angle of 90 degrees without micro-optic elements. The flexible polymeric optical waveguide was fabricated with a design that enables it to be easily bent within an adapter to permit change of optical path. For the fabrication of the flexible polymeric optical waveguide, a hot embossing technology was used, which offers the advantages of ease of mass production and reproducibility. By using a photo-resist (PR) e...