| 摘要 |
PURPOSE:To automatically adjust the amplitude of an input light signal by attenuating a light signal to pass through the light input passage of a light electric converting circuit in accordance with the amplitude of the light signal. CONSTITUTION:From the output electric signal of a light electric converting circuit 2, a control signal corresponding to the amplitude of an input light signal, especially, the peak signal amplitude is generated, and in accordance with the control signal, a variable light attenuator 12 is controlled. As the variable light attenuator 12 in this case, one side uses the element with a different transmission characteristic according to the position, changes mechanically the position with a control signal, and other side is composed of the light integrated circuit equipped with the dielectric waveguide and the electrode connected to the dielectric waveguide. By the control signal, a voltage impressed to the electrode is changed and the attenuating quantity of the light signal to pass through the dielectric waveguide is changed. Thus, a light electric converting circuit and a receiving circuit are not saturated and the amplitude of the input light signal can be automatically adjusted. |
