BIAS CIRCUIT OF EXTERNAL MODULATOR

• Main Authors: HORIO TAKEO, TAKAHASHI TOMOKAZU
• Format: Patent
• Language: English
• Published: 30.07.2009
• Subjects: DEVICES OR ARRANGEMENTS, THE OPTICAL OPERATION OF WHICH ISMODIFIED BY CHANGING THE OPTICAL PROPERTIES OF THE MEDIUM OF THEDEVICES OR ARRANGEMENTS FOR THE CONTROL OF THE INTENSITY,COLOUR, PHASE, POLARISATION OR DIRECTION OF LIGHT, e.g.SWITCHING, GATING, MODULATING OR DEMODULATING; FREQUENCY-CHANGING; NON-LINEAR OPTICS; OPTICAL ANALOGUE/DIGITAL CONVERTERS; OPTICAL LOGIC ELEMENTS; OPTICS; PHYSICS; TECHNIQUES OR PROCEDURES FOR THE OPERATION THEREOF

PROBLEM TO BE SOLVED: To provide a bias circuit of an external modulator in which fluctuation of a DC bias is suppressed, and a connection part between the external modulator and the bias circuit is downsized. SOLUTION: A DC bias means has: an adjusting voltage setting means for setting adjusting voltage for supplying optimal DC bias voltage to the external modulator; a control transistor which constitutes a constant current source for supplying the DC bias current to a terminal resistor connected in parallel with the external modulator; and a buffer amplifier which supplies fixed bias voltage based on the adjusting voltage to the control transistor. COPYRIGHT: (C)2009,JPO&INPIT