| 摘要 |
PROBLEM TO BE SOLVED: To obtain the optical receiver over a broad band without deteriorating the S/N by selecting a current of a current source below a current expressed in a specific equation. SOLUTION: A circuit regarded to be equivalent to a current source I with a current ia is connected between ground and a connecting point between an anode of a PIN photo diode D1 being a reception element an input terminal of an amplifier AMP. A polarity of a current of the current source I is positive when a current is directed to an input terminal of the amplifier AMP. In this equivalent circuit, the current ia is expressed as ia=i×(R+RF/A)/(R+1/jωCJ). In this case, the equation expressing a voltage vo at an output terminal of the amplifier AMP by the current (i) of a current source being the equivalent circuit being an input signal is not a function of the frequency. Furthermore, the current ia of the current source I is to be the current expressed by the right-hand side of the equation above or below. In this case, the frequency characteristic of the photodiode D1 is compensated and improved depending on the current ia of the current source I. |
