| 摘要 |
PURPOSE:To obtain a titled optical modulator of a small-sized and simple constitution, and also to raise a life characteristic by eliminating a rotary part by using both fixed and movable slit plates as a modulating means, and driving the movable slit plate by a bimorph. CONSTITUTION:An AC driving power source 20 for driving the bimorph 12 is provided. In this case, in a light transmitting position, both light transmitting parts 17, 18 coincide exactly, and in a light shielding position, mutual light shielding parts are closed each other and shield the light exactly to obtain the max. output of a photodetector 7. The adjusting means 22 of a modulating means 11 is provided on a driving power source circuit 21 so that a DC bias is superposed and impressed to a driving power source 20. When the DC bias is impressed the bimorph 12 is inclined and moved in the upper or lower direction. That is to say, the operating point is shifted up and down in proportion to the impressed DC voltage, and the vibration of a prescribed amplitude is executed by the driving power source by basing on its point as a reference. In this way, by executing an adjustment by the DC bias, difference of a light quantity of the light shielding time and the light transmitting time, namely, a modulation efficiency can be raised. |
