Low cost GaAs MESFET and InP HFET technologies for 40 Gb/s OEICs

40 Gb/s are expected to become the future standard fiber-optic operating speed for the datacommunication and telecommunication systems. High performance and low cost technologies are required to lower the system cost, yet maintain the overall performance. In this paper, a state of art ion implant GaAs MESFET and a simple layer structure InP/InGaAs doped channel HFET were described, compared and proposed for 40 Gb/s OEICs. We have developed 0.10 um gate direct ion implanted GaAs E/D MESFET process with current cutoff frequency (ft) of 120 GHz which is the highest reported ft for 0.1 um gate MESFET device. Based on this result, we believe a low cost solution of ion implant GaAs MESFET with ft greater than 200 GHz process is achievable in the near future with 0.05 um gate. The 0.14 um InP/InGaAs doped channel HFET has ft of 188 GHz, which is the highest reported doped channel HFET device. The measured device performance of both devices are described in the paper. Compared to the epitaxial device, the ion implant MESFET has the significant advantage in the low cost solution of 40 Gb/s OEIC. The doped channel HFET provides superior performance than MESFET, yet it needs only 5 epitixal layers which provide advantage over HEMT device. 40 Gb/s OEIC receiver was studied and designed using HFET HSPICE model. The simulation shows the circuit has bandwidth of greater than 30 GHz with greater than 40 dB ohms gain which make it suitable for 40 Gb/s application. Using this circuit, a 1×4 OEIC receiver array in a Wavelength Division Multiplexing (WDM) system will have overall data rate of 160 Gb/s.