LOW-LOSS FIBER-MATCHED LOW-TEMPERATURE PECVD WAVE-GUIDES WITH SMALL-CORE DIMENSIONS FOR OPTICAL COMMUNICATION-SYSTEMS

Plasma-enhanced chemical vapor deposition (PECVD) offers a simple way of fabricating (doped) silica layers on silicon. A new design of the w aveguide core allows low-loss fiber matched waveguides with low birefr ingence without high-temperature annealing. The increased loss of dope d plasma deposited silica due to hydrogen incorporation is overcome by reducing the core dimensions and increasing the refractive index cont rast. The waveguides can easily be fabricated using standard PECVD tec hnologies and resist masked reactive ion etching (RIE) etching. Integr ated optical devices such as 1 x 8 power splitters, 1300/1550-nm wavel ength multiplexers and thermooptical switches were successfully fabric ated and tested.