Development of novel board-to-board connectors based on tightly bent fibers for optical backplanes

Abstract

The development of optical boards is inspired by increasing bandwidth requirements in servers,

switches and supercomputers because at high bandwidth the conventional copper wire is not a

viable link. These bandwidth thirsty devices consist of multiple racks where each rack has a

backplane and multiple daughter cards in a blade structure. For an effective transition from an

electrical link to an optical link, a 90o optical bending structure at the backplane-daughter card

interface should be addressed well. In this paper, we presented a novel board-to-board connector by

bending a low bending loss fiber tightly in a delicate support structure. We used micro-milling and

deep proton writing (DPW) technology to fabricate the connector parts. DPW is a rapid prototyping

technology for the fabrication of micro-optical and micro-mechanical components. The connector

assembly is very compact with 7mm X 6.5mm X 4.5mm and it has four optical fiber channels. We

tested the component prototype and measured a coupling loss as low as 0.2dB by using a laser

source. The optical performance when it is integrated into optical waveguides in printed circuit

boards is evaluated and confirms better than state-of-the-art performers. The total loss, which

combines loss of the connector and simulated waveguide to connector coupling losses, is 2.6dB.

This is an important breakthrough in the transition from an electrical backplane to an optical

backplane.

Date of Award	2011
Original language	English
Supervisor	Michael Vervaeke (Promotor), Jürgen Van Erps (Promotor) & Christof Debaes (Advisor)