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 multimode optical fiber and laser sources is disclosed in which an annular beam is generated by the laser source, thus preventing center fiber transmission modes from reaching the detector. This prevents or lessens a pulse-splitting effect at the detector. The annular beam is generated by configuring a vertical cavity surface emitting laser to have a center totally-reflecting block of 5-7 microns to generate a substantially dark-centered beam.