| 摘要 |
PURPOSE:To facilitate adjustment of the characteristics of a processing circuit by applying a light to a necessary one of conductors for adjustment of the characteristics through a transparent part of a package and by cutting it thereby. CONSTITUTION:A light transmitted from a transmitter 51 is sent to a receiver 52 through an optical fiber 53. The transmitter 51 and the receiver 52 are constructed of RED (light-emitting diode) 56 driven by a drive circuit 55 and of a comparator circuit 59 wave-shaping a voltage signal obtained by converting a light detection current signal of a PIN diode 57 by a current/voltage conversion amplifier 58, respectively. They are accommodated in transparent packages 51a and 52a respectively. The circuit 55 is provided with conductors for adjustment of characteristics and the circuit characteristics are changed by cutting the conductors. On the occasion, these conductors for adjustment of characteristics are made cuttable by application of a laser beam. Accordingly, the conductors can be cut by the application of light through the transparent part of the package 51a, and thus the adjustment of characteristics can be conducted easily without need to open the package 51a. |
