Circuit for amplitude modulation of a laser drive signal

摘要

The circuit arrangement creates the precondition for a control method by means of which the emitted optical power of the laser can be kept constant (stabilised) independently of temperature and ageing. These circuit arrangements are normally designed as three-stage cascade circuits which are supplied with operating voltages of more than 5V. The aim according to the object is to specify a circuit arrangement which can be operated universally in a temperature range of T = -40 DEG C to 100 DEG C for commercially-available lasers and which can be supplied from a standard 5V voltage source. According to the invention, differential amplifiers (T1, T2) which act as current switches are arranged for this purpose in a first cascade stage, and the current sources which supply the differential amplifiers (T3, T4) are arranged in a second cascade stage. A data signal (D) which is used for controlling the modulation current (Imod) is logically related to a pilot signal (P), which is used for controlling the pilot currents (Ip1, Ip2), in at least one cascade stage.