The primary objective of this proposal is to overcome the current technological difficulties associated with the production of efficient, high power (1 mW) AlGaInP-based visible vertical cavity surface emitting laser (VCSEL) arrays capable of operating at 50°C. In particular the consortium wishes to develop a 1 x 8 VCSEL array operating at 650 nm that is coupled, in a self-aligning fashion, to a multimode plastic fibre ribbon. This module will in principle form the basis of a cheap, rugged and high data-rate optical interconnect system designed to operate at the attenuation minimum of low cost plastic fibre.
As copper co-axial cable approaches its ultimate limit in data band-width, the demand for a widespread and high speed optical distribution of data becomes ever more acute. A particularly attractive solution to this problem is based upon the parallel transmission of data over multimode plastic fibre ribbon using arrays of VCSELs as the optical source. The combination of the VCSELs intrinsic high speed, planar geometry and almost ideal beam profile coupled with the exceedingly low cost of plastic fibre make this a potentially very low cost and high data rate (> 1 Gbit/s) distribution system. Although such systems are being developed using a range of different wavelengths, no VCSEL operating at 650 nm is currently capable of meeting system specifications. This consortium proposes to fill this technological gap.
The consortium partners propose to accomplish this objective by distributing effort across four areas. Firstly VCSELs will be fabricated using both conventional and hybrid designs. Conventional VCSELs use all semiconductor Distributed Bragg Reflector (DBR) mirrors, while the higher risk hybrid designs use dielectric based DBR mirrors. This dual approach to VCSEL fabrication is intended to increase the likelihood of achieving the necessary device specifications. Secondly, we will make an investigation of the device physics governing visible VCSELs. By a combination of theoretical device modelling and employing a range of experimental techniques it is anticipated that a thorough understanding of visible VCSEL loss mechanisms and thermal behaviour will be achieved thereby allowing laser designs to be optimised. Thirdly, we propose to develop a low cost, rugged and self-aligning plastic fibre-to-VCSEL array process and hence produce a prototype module. Fourthly, a feasibility study will be made of the capacity of these devices and modules to be mass produced using multi-wafer growth reactors. This manufacturability study will also include a measurement of visible VCSEL life-times.
Funding SchemeCSC - Cost-sharing contracts
5656 AA Eindhoven
S10 2TN Sheffield
GU2 5XH Guildford