Feedforward LF compensation for laser fibre optic transmitter

Direct intensity modulation of laser optical power is probably the one most often used in practice. Classical circuits for semiconductor laser driving are not suitable for operation with unbalanced codes or data transmitted i n the form of bursts. The reason for this is a low-frequency (LF) cut-off c aused by the laser stabilising circuit. In the paper a concept is presented , along with practical realisation of the laser driving and stabilising cir cuit for unbalanced codes or burst-mode transmission. A developed circuit a llows modulation of the laser diode from DC up to the maximum modulation fr equency of the laser. Experimental data including pulse tests, eye pattern test and thermal properties of proposed solutions are presented.