| 摘要 |
PURPOSE:To amplify a stable optical signal by providing a drive means driving an electrooptic conversion element by a current proportional to a difference between a photovolatic current of the 1st photoelectric conversion element and a photovolatic current of the 2nd photoelectric conversion element so as to feedback part of an optical output to the input. CONSTITUTION:Let a noninverting input light (positive optical input) be P11, an inverting input light (negative optical input) be P12, then the input lights P11, P12 are converted respectively into photovolatic currents IP1, IP2 by two photo diodes (photoelectric conversion elements) PD1, PD2. An amplifier A amplifies the difference between the photovolatic currents IP1, IP2 to supply a forward current IF of a laser diode (electrooptic conversion element) LD. Thus, the laser diode LD generates an optical output P0. A light kP0 proportional to the output light P0 from the laser diode LD is fed back to the photo diode PD2. When the current amplification factor is sufficiently large, the relation of P0=1/k(P11-P12), k>=0 is obtained and then the output light P0 is proportional to the difference (P11-P12) of the two input lights. |
