Amplitude modulation circuit for laser drive signal - has first and third voltage-controlled current sources connected to first differential amplifier, and second current source connected to second

First (T1,T4) and second (T2,T3) differential amplifiers are arranged in a first cascade stage. The first and second inputs of the differential amplifiers are respectively connected to each other. The first and second outputs are connected cross-wise. First, second and third voltage controlled current sources driven commonly from a control voltage form a second cascade stage. The first current source which supplies the modulation current (Imod), and the third current which supplies the second pilot current (Ip2) are connected to the first differential amplifier. The second current source, which supplies the first pilot current (Ip1) is connected to the second differential amplifier. The second and third current sources are activated alternately depending on a pilot signal (P,P-). USE/ADVANTAGE - Universally applicable to customary semiconductor lasers. Can be operated from 5 V standard voltage source and realised as monolithic IC.