60 GHz Analog Radio-Over-Fiber Single Sideband Transmitter Chipset With 55nm SiGe BiCMOS Driver RFIC and Silicon Photonics Modulator PIC

Abstract

An all-silicon analog radio-over-fiber transmitter chipset is presented for narrowband operation in the unlicensed 60 GHz V-band for use in low-cost and low-power distributed antenna systems. The chipset consists of a low-noise high-speed quadrature driver RFIC and an EAM based single-sideband I/Q modulator PIC. Resonant matching is used to drive the EAMs which provides 6 dB more gain compared to an on-chip 50 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\Omega$</tex-math></inline-formula> resistive termination. A further 6 dB improvement is had by placing the quadrature hybrid on the RFIC before the output stages compared to implementations that place the hybrid on the PIC. The RFIC consists of a low-noise input stage, gain stages, a hybrid coupler and two output stages while the PIC consists of parallel electro-absorption modulators and thermo-optic phase shifters. A sideband suppression ratio of 25 dB is demonstrated with a full chipset size of 1.1 mm <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^{2}$</tex-math></inline-formula> and a power consumption of 45 mW. Succesful optical back-to-back experiments were conducted using various QAM signals.