| 摘要 |
<P>PROBLEM TO BE SOLVED: To reduce intensity fluctuation of light intensity modulation signal light with the light intensity subjected to on/off modulation. <P>SOLUTION: This optical noise reduction circuit has: a light branch means to branch a part of input signal light; a light detection means to detect light intensity of the branched signal light A; a light intensity modulation means to modulate light intensity of signal light B from the light branch means, and having a transmission characteristic having a sinusoidal wave-like form with respect to an application voltage; a drive means to drive the light intensity modulation means based on a detection signal of the light detection means; and a delay adjustment means to adjust timing between a signal application time to the light intensity modulation means by the drive means and a light signal input time to the light intensity modulation means to negate light intensity change for the light intensity modulation means based on the light intensity detected by the light detection means. For the bias of the light intensity modulation means, the operation point at an on-level of the input level is set at a point where the gradient of the transmission characteristic is -1, and each of the light detection means, the light intensity modulation means and the drive means, has a band equal to or higher than the symbol rate of a light intensity modulation signal. <P>COPYRIGHT: (C)2011,JPO&INPIT |
