High-tolerance broadband-optical switch in planar lightwave circuits

摘要

A broadband optical switch with high process tolerance designed and fabricated using Planar Lightwave Circuits (PLC) technology. A 2x2 configuration of the switch is based on a Mach-Zehnder interferometer (MZI) configuration that includes two 3 dB adiabatic couplers and two identical arms. Each adiabatic coupler is characterized by two straight branches having different widths, separated over a coupling length by a changing spacing therebetween and blending in a symmetric intersection area, which connect to two symmetric branches. The two adiabatic couplers are connected by the two arms with their symmetric branches facing each other along an optical propagation axis. Switch control is realized by changing an optical property of one or both of the MZI arms. Implementation in silica-on-silicon PLCs provides switches with an exceptional broadband range (1.2-1.7 mum), very high extinction ratios (>34 dB), low fabrication sensitivity and polarization independent operation.