A Monolithically-Integrated Chip-to-Chip Optical Link in Bulk CMOS

作者：Sun Chen^*; Georgas Michael; Orcutt Jason; Moss Benjamin; Chen Yu Hsin; Shainline Jeffrey; Wade Mark; Mehta Karan; Nammari Kareem; Timurdogan Erman; Miller Daniel; Tehar Zahav Ofer; Sternberg Zvi; Leu Jonathan; Chong Johanna; Bafrali Reha; Sandhu Gurtej; Watts Michael; Meade Roy; Popovic Milos; Ram Rajeev; Stojanovic Vladimir

来源：IEEE Journal of Solid-State Circuits, 2015, 50(4): 828-844.

DOI：10.1109/JSSC.2014.2382101

• Memory
• optical interconnects
• optoelectronics
• process integration
• silicon-photonics
• wireline transceivers

Silicon-photonics is an emerging technology that can overcome the tradeoffs faced by traditional electrical I/O. Due to ballooning development costs for advanced CMOS nodes, however, widespread adoption necessitates seamless photonics integration into mainstream processes, with as few process changes as possible. In this work, we demonstrate a silicon-photonic link with optical devices and electronics integrated on the same chip in a 0.18 mu m bulk CMOS memory periphery process. To enable waveguides and optics in process-native polysilicon, we introduce deep-trench isolation, placed underneath to prevent optical mode leakage into the bulk silicon substrate, and implant-amorphization to reduce polysilicon loss. A resonant defect-trap photodetector using polysilicon eliminates need for germanium integration and completes the fully polysilicon-based photonics platform. Transceiver circuits take advantage of photonic device integration, achieving 350 fJ/b transmit and 71 mu A(pp) BER = 10(-12) receiver sensitivity at 5 Gb/s. We show high fabrication uniformity and high-Q resonators, enabling dense wavelength-division multiplexing with 9-wavelength 45 Gb/s transmit/receive data-rates per waveguide/fiber. To combat perturbations to variation-and thermally-sensitive resonant devices, we demonstrate an on-chip thermal tuning feedback loop that locks the resonance to the laser wavelength. A 5 m optical chip-to-chip link achieves 5 Gb/s while consuming 3 pJ/b and 12 pJ/bit of circuit and optical energy, respectively.

• 出版日期2015-4
• 单位MIT