Abstract

Efficient high speed optical switches and amplitude modulators will be important components for utilizing the large available bandwidth of single-mode lightwave systems. In addition to amplitude modulation for digital coding, fast optical switches may prove very useful for high speed time division multiplexing. Presently several guided-wave optical switch/modulators have been reported with demonstrated modulation bandwidth of approximately 1 GHz.^1,2 For high speed operation, accurate switching speed measurements under electrical pulse operation are hampered by the finite speed of the pulsing circuit and the photodetector. Generally it is necessary to estimate the actual device switching time by deconvolving the response time of the pulser and detector from the measured output optical pulse.¹ We have developed a novel measurement technique utilizing picosecond optical pulses to overcome some of these limitations. In a parallel effort we have designed and fabricated very short length (L = 750 μm) switched directional couplers using Ti-diffused lithium niobate waveguides which can be modulated with 6 volts. Using our novel measurement technique, preliminary results indicate a switching rate of at least 5 GHz with this device.

© 1980 Optical Society of America