導波路型フレネル光変調器および光走査器

抄録

This paper describes two novel electrooptic devices based on an one-dimensional Fresnel lens consisting of Ti-diffused channel waveguides on a LiNbO₃ crystal. One is a Fresnel light modulator (FLM) by which the main lobe of diffraction pattern near the focal point is modulated with an applied voltage while focusing is almost kept. The basic parameters of the FLM with 13 zones at 633nm are: the focal length (f) is 12.413mm, the full width of beam at half power (W) 56μm, thehalf-wave voltage 28V, the extinction ratio 18.1dB and the insersion loss 10.1dB.
The other is a Fresnel light scanner (FLS) by which the main lobe of diffraction pattem in the focal plane is continuously scanned as a function of voltage. The experimental results of the FLS with 20 zones at 633nm are as follows: fis 2.5cm, Wis 16-20μm and the num ber of resolvable spots following the Rayleigh resolution criterion is 2.2.
The FLM is apPlicable to a diffraction limited aberration-free lens and high optical power modulator. The FLS has attractive functions such as lensless light scanning and linear light modulation.