An output current waveform compensation technique for ultra-high speed VCSEL driver

In order to improve the eye diagram performance of output current in vertical-cavity surface-emitting laser (VCSEL) driver, the influence made by bond wire on high speed output waveform is discussed in this paper, based on a practical VCSEL model with bond wire inductance. A technique based on pre-emphasis is used to compensate the output current waveform. And by analyzing the waveforms in time domain, a conclusion is drawn that the optimal delay time for compensation is equal to the period of output ringing. The effectiveness of this compensation technique is verified by model simulation result and post-simulation result of a 22Gb/s VCSEL driver circuit in 65nm CMOS process.