40 Gbit/s reshaping amplifier cell

The design of a 40 Gbit/s reshaping amplifier cell with 6 dB gain and a 2 V output signal for ETDM transmission system is presented. The switching-speed of the structure is improved, as well as the reshaping and the limiting effects, by optimising the transistor sizes, DC operating points and the layout design. The chip is fabricated in a GaAs p-HEMT technology with typical Ft of about 95 GHz, using microstrip transmission lines. Careful layout analysis is performed to optimise propagation phenomena and to minimise interconnection parasitic elements.