| 摘要 |
PURPOSE:To realize an optical amplifier generating a light output proportional to the difference between two light inputs with very simple circuit constitution by allowing a drive means to drive an electrooptic conversion element by a current proportional to the difference between both photovolatile currents of the 1st and 2nd photoelectric conversion elements. CONSTITUTION:An amplifier A amplifies the difference between the photovolatile currents IP1, IP2 of photodiodes PD1, PD2 to supply a forward current IF to a laser diode (electrooptic conversion element) LD. Thus, the laser diode LD generates a light output P0. Let the current amplification factor of the amplifier A be beta, then the forward current IF of the laser diode LD is expressed as IF=beta(IP1-IP2). When the current amplification factor beta is sufficiently large, the light output P0 is expressed as P0=1/k(P11-P12) and the reciprocal of the feedback quantity of the light output P0 is the amplification factor of the circuit. The light output P0 is proportional to the difference of inputs (P11-P12). |
