| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To realize optical modulation with excellent efficiency even in ultrahigh frequencies, whereas in a conventional semiconductor puls light source comprising a semiconductor laser and an optical modulator combined together, a chip capacitor is arranged in the vicinity of the optical modulator, wherein both are connected to each other with a gold wire in order to reduce electric reflection in a modulated frequency from the optical modulator, however, under the influence of characteristics of the inductance of the gold wire and chip capacitor the optical modulation efficiency lowers at tens of GHz or higher frequencies. <P>SOLUTION: The efficiency on the high frequency side is improved by shortening the length of the gold wire, that is, by lowering the inductance of the gold wire by disposing the capacitor adjacent to the optical modulator on the same substrate as that of the optical modulator. Also a loss due to a bias tee is reduced by directly applying a DC bias voltage to the optical modulator via the capacitor without using the bias tee. <P>COPYRIGHT: (C)2004,JPO&NCIPI</p> |
