| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To suppress a noise component even when a phase difference between two signals to be used for optical modulation deviates from 90°and to suppress a third order side band with the highest signal intensity among side bands with third or higher odd-numbered orders while using optical SSB modulation. <P>SOLUTION: The low-noise optical frequency conversion device is equipped with a Mach-Zehnder interferometer type SSB modulator with first and second Mach-Zehnder interferometer type phase modulators arranged on respective optical paths, first and second electrodes to control optical wave phases arranged on the first and second Mach-Zehnder interferometer type phase modulators, a third electrode to control phases of optical waves propagated through respective arms of the SSB modulator, a means to input a high frequency electric signal, a means to divide the high frequency electric signal into two signals with a phase difference of nearly 90°between each other and a means to supply these signals. Besides the conversion device is constructed so as to suppress the noise component included in an output of the SSB modulator by varying a bias voltage to be applied to the third electrode corresponding to the phase difference between the two signals with the phase difference of nearly 90°. <P>COPYRIGHT: (C)2004,JPO</p> |
