The InP-HEMT IC Technology for 40-Gbit/s Optical Communications

Abstract

We present the outline of the InP HEMT IC technology. This technology realizes InP HEMT digital ICs for 40-Gbit/s optical fiber communication systems through the integration of 0.1-μm-gate-length HEMTs, vertical diodes, capacitors, and WSiN resistors with two level interconnections. This paper describes the high-speed digital IC circuit design and fabrication in InP HEMT technology for 40-Gbit/s/channel optical communication systems. Some results on InP HEMTs' reliability are also covered. Basic circuit design techniques utilizing SCFL topology and fundamental circuit elements of the selector and D-type flip-flop are discussed in detail. The basic digital ICs of MUX, D-FF, and DEMUX ICs fabricated with 0.1-μm-gate InP HEMTs successfully operated up to 50 Gbit/s in the packaged modules. These IC modules offer large speed margins for the 43-Gbit/s OTU-3 data rate. In order to develop cost-effective optical transmitters and receivers, we designed a PLL-based CDR with a full-rate architecture. The fully monolithic integrated CDR exhibited error-free operation for 231-1 PRBS data signal at the OTU-3 bit rate of 43.0184 Gbit/s. Four-bit MUX and DEMUX ICs are other key components, and could be implemented by using InP HEMT technology. Additionally, we describe InP-IC fabrication technology with two-level inter-connection. This is already fully matured for 40-Gbit/s SSI fabrication. The uniform FET characteristics and high-yield passive component fabrication technologies support this degree of maturity. InP HEMT lifetime is 107 hours at l00°C. These results prove the InP HEMT IC fabrication technology presented here, to be highly reliable. These investigation show that robust performance and yield when realizing SSI and MSI 40-Gbit/s functions.