All-optical modulation with anomalous photovoltaic film on a Ti:LiNbO↓（3） waveguide modulator

摘要

An anomalous photovoltaic film formed by simultaneous oblique sputter deposition of CdTe and CdS from different directions was integrated onto LiNbO↓(3) and combined with a Mach-Zehnder-type interferometric waveguide modulator. Irradiation by 830-nm laser light with low intensity near 1 mW of the photo-voltaic film induced anomalous photovoltages of-5 V, which is as high as the half-wave voltage. This photovoltage was used to control the signal light in the waveguide. Modulation by external light was demonstrated with a response time of 0.1 s. Because of the presence of CdS with a photoconductive effect, the response time was much faster than that of conventional anomalous photovoltaic films formed by oblique deposition of CdTe. # 1997 Optical Society of America