Characterization of organic multi‐mode optical waveguides for electro‐optical printed circuit boards (EOPCB)

Abstract

Purpose

To characterise the optical performance of organic multi‐mode optical waveguides integrated with printed circuit board (PCB) and to demonstrate the feasibility of 2.5 and 10 Gbps optical interconnection in board‐level, respectively.

Design/methodology/approach

This paper provides both qualitative and quantitative approaches for the characterization the wave guide performance, i.e. using loss measurement, optical beam profiling, ethernet verification, and eye‐diagram testing. In addition to wave guide loss measurement, the most significance part of the work reported in this paper is to evaluate optical wave guides with coupled VCSELs, by which a 3 dB coupling design budget can thus be identified. Furthermore, by artificially manipulating coupling conditions, practical concerns of EOPCB integration, including waveguide geometry, VCSEL driving power, alignment tolerance, coupling spacing, etc. are studied.

Findings

Thermal stability studies related to PCB lamination processes show the feasibility of organic waveguides integrated to traditional PCB manufacturing. For a direct VCSEL/PD coupling scheme, a 3 dB power budget is experimentally identified. For short reach optical interconnection, 10 Gbps up to 17 cm propagation on PCB can be achieved by using 50×50 μm multi‐mode organic waveguides, where a±25 μm tolerance of optical alignment is compatible to the design rules of PCB.

Originality/value

The value of the paper lies in its systematic approaches to identify the waveguide performance through both qualitative and quantitative indices. The correlation between geometry design, processes, coupling conditions, and optical performance of organic waveguides explored in detail. Not only is a standard eye‐diagram test used to verify the waveguide at 2.5 and 10 Gbps bandwidth, but also a prototype of optical data‐communication on giga‐ethernet is demonstrated for long term stability. Following these analytical methods, readers can understand more about the optical performance of waveguides when designing optical interconnection for high speed electro‐optical integrated PCBs.

Citation

Shen, L., Lo, W., Chang, H., Fu, H., Lee, Y., Chen, Y., Chang, S., Chen, W. and Chou, M. (2006), "Characterization of organic multi‐mode optical waveguides for electro‐optical printed circuit boards (EOPCB)", Circuit World, Vol. 32 No. 1, pp. 8-15. https://doi.org/10.1108/03056120610616508