THERMOOPTICAL MODE EXTINCTION MODULATION IN POLYMERIC WAVE-GUIDE STRUCTURES

Thermo-optic mode extinction modulation was demonstrated in polymeric waveguide structures. A strip heater was used to control mode extincti on via the thermo-optic effect. Mode extinction occurs due to the coun teracting effect which arises from a polymeric waveguide with a negati ve thermo-optic coefficient and a glass substrate with a positive coef ficient. Complete mode extinction was achieved at a low driving voltag e (1.6 V). Several devices were fabricated and tested using sine and s quare wave ac voltages up to 40 kHz. Switch ON and OFF times in the mi llisecond range were obtained. All devices were made of commercially a vailable clear polyurethane varnish on BK-7 glass substrates.