| 摘要 |
An analog photodiode module converts the light including many AM signals of different frequencies into electric signals. It is desirable to suppress the distortion caused by the non-linearity of the light-current conversion in the PD module (3, 4) as completely as possible. Extreme convergence of beams enhances the sensitivity but raised the distortion. Prior modules suppressed the distortion at an expense of the sensitivity. Present invention positions the end of the fiber (8) at a point which is closer to the lens (5) than the maximum sensitivity range and give distortion smaller than the predetermined value. The high sensitivity and the low distortion are compatible at the point. <MATH> |
