Amplitude modulation circuit for laser drive signal - has differential amplifiers respectively connected to second pole of operating voltage source via voltage controlled current sources

摘要

First (T1,T2), second (T3,T4) and third (T5,T6) differential amplifiers are connected together so that the respective first outputs are connected to a first pole of an operating voltage source. The second outputs are connected via the laser (LD) to the first pole of the operating voltage. The inputs of the differential amplifiers are connected to a combinational logic circuit (L) controlled by one of a data signal (D) and a pilot signal (P). Each differential amplifier is respectively connected to the second pole of the operating voltage source (VEE) via a voltage controlled current source (IP1,IP2,Imod). The voltage controlled current sources have their control inputs commonly connected to a control circuit output. ADVANTAGE - Universally applicable to customary semiconductor lasers can be operated from 5 V standard voltage source, and can be realised as monolithic integrated circuit.