METHOD AND SYSTEM FOR PREVENTING LOW ORDER OPTICAL TRANSMISSION MODES IN A MULTIMODE OPTICAL FIBER COMPUTER NETWORK USING AN ANNULUS LASER

摘要

A method for improving modal bandwidth in computer networks using multimodeoptical fiber and laser sources is disclosed in which an annular beam isgenerated by the laser source, thus preventing center fiber transmission modesfrom reaching the detector. This prevents or lessens a pulse-splitting effectat the detector. The annular beam is generated by configuring a verticalcavity surface emitting laser to have a center totally-reflecting block of 5-7microns to generate a substantially dark-centered beam.