Simple technique for bandwidth enhancement ofmultimode fibre links using controlled spatial emissionfrom vertical cavity surface emitting lasers

Abstract

High performance etched vertical cavity surface emitting laser sources are reported that avoid bandwidth collapse in multimode fibre by using a simple coupling technique to control the launch. These sources allow optimum link bandwidths of 2 Gbit/s over 500 m of fibre when aligned for maximum launch power, and maintain over-filled launch bandwidths for alignment tolerances of ±7 µm.