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The first results of an integrated hybrid photo-receiver based on a 850 nm two-terminal (2T) silicon germanium (SiGe) heterojunction bipolar photo-transistor (HPT) for low-cost radio-over-fibre (RoF) applications is presented. A hybrid module was realised with two cascaded low-noise amplifiers of 20 dB total gain and an SiGe 2T-HPT exhibiting a −15 dB opto-microwave gain at 5.15 GHz with a 1.6 GHz bandwidth. A 16% degradation of the error vector magnitude compared with back-to-back measurement for the transmission of a 2 GHz OFDM signal at 3 Gbit/s was measured based on the 60 GHz IEEE 802.15.3c standard transposed at the intermediate frequency (IF) of 5 GHz, according to an IF-RoF distribution mode.

Micron dimensioned on-chip optical links of 50 micron length, utilizing 650 -850 nm propagation wavelength, have been realized in a Si Ge bipolar process. Key design strategies is the utilization of high speed avalanche based Si light emitting devices (Si Av LEds) in combination with silicon nitride based wave guides and high speeds Si Ge based optical detectors. The optical source, waveguide and detector were all integrated on the same chip. TEOS densification strategies and state of the art Si-Ge bipolar technology were further used as key design strategies. Best performances show up to 25 GHz RF carrier modulation and -40dBm total optical link budget loss with a power consumption of only 0.1 mW per GHz bandwidth. Improvement possibilities still exist. The process used is in regular production. The technology is particularly suitable for application as optical interconnects utilizing low loss, side surface, waveguide to optical fibre coupling.

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