| 摘要 |
<P>PROBLEM TO BE SOLVED: To control input signal amplitude inputted to an MZ (Mach-Zehnder) optical modulator so as to automatically be a half wavelength voltage Vπ and to dispense with adjustment for every optical transmitter when the optical transmitters are manufactured and assembled. <P>SOLUTION: A low frequency signal is superposed on bias voltage to drive the MZ optical modulator, a portion of an obtained optical output signal is monitored by an optical detector, the direct current component of its value is extracted by a low pass filter and the amplitude of a digital input signal inputted to the MZ optical modulator is controlled by using output of a differential amplifier detecting difference between the output of the low pass filter and a standard voltage. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
