| 摘要 |
PURPOSE:To measure the frequency modulation component of a signal to be measured without receiving the effect of amplitude modulation component by utilizing a difference between the signals of two output ports of a Mach-Zehnder interferometer as observed output. CONSTITUTION:Two photoelectric converters 2 and 3 are connected in series so that the potential of the anode side of the converter 2 and the potential of the cathode side of the converter 3 are added as an electric circuit means which outputs the difference between the electrical signals outputted from the converters 2 and 3 as the output signal, which is transmitted to an output terminal 5 through an amplifier 4. A heater 6 is provided in the Mach-Zehnder interferometer 1 as a means for controlling the difference between two lengths of optical paths and a control circuit 8 which gives control input in accordance with the difference between the output electrical signals is connected to the control electrode of a transistor 7 which controls the current of the heater 6. Furthermore, optical wave guides 13 and 14, light input ports 11 and 12, directional couplers 15 and 16 and light output ports 17 and 18 are also provided in the interferometer 1. By utilizing the difference between the signals of the ports 17 and 18, the frequency modulation component can be measured. |
