摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide an optical modulator that is high in efficiency and accuracy by improving an electric circuit for driving the optical modulator. <P>SOLUTION: The distributed low-pass filter transmission line circuit apparatus comprises: input and output microstrip lines (20, 24), which have a length of less than a quarter of a target wavelength corresponding to a target operating frequency, respectively, which exhibits characteristic impedance exceeding a target signal source impedance, and which exhibits a series inductance which is the target operating frequency; and an electro-absorption optical modulator (12) comprising a signal electrode (44), the length of which is less than a quarter of the target wavelength, the characteristic impedance of which is less than the target signal source impedance, and which exhibits a by-pass capacitance that is the target operating frequency. They are incorporated as the distributed low-pass filter transmission line circuit (10), which exhibits characteristic impedance that is substantially matched with the target signal source impedance at the target operating frequency. <P>COPYRIGHT: (C)2005,JPO&NCIPI</p> |