Photonic page buffer based on GaAs multiple-quantum-well modulators bonded directly over active silicon...

Area of Science:

• Optoelectronics
• Integrated Photonics
• Semiconductor Device Physics

Background:

• The increasing demand for high-speed data processing necessitates advanced buffering solutions.
• Existing electronic buffers face limitations in speed and bandwidth for optical data.
• Vertical integration of optical and electronic components is crucial for next-generation computing.

Purpose of the Study:

• To demonstrate a novel photonic first-in, first-out (FIFO) page buffer.
• To achieve high-speed, nonvolatile data buffering for optical interconnects.
• To showcase the vertical integration of optoelectronic devices with silicon VLSI.

Main Methods:

• Fabrication of a 2-kbit photonic page buffer using gallium arsenide/aluminium-gallium arsenide multiple-quantum-well diodes.
• Flip-chip bonding of quantum-well diodes to submicrometer silicon complementary-metal-oxide-semiconductor (CMOS) circuits.
• Integration of multiple-quantum-well modulators and detectors directly over active silicon VLSI.

Main Results:

• Achieved a data rate of 50-Mpage/s.
• Demonstrated nonvolatile storage, asynchronous-to-synchronous conversion, and bandwidth smoothing.
• Verified tolerance to jitter/skew, spatial format conversion, and wavelength conversion.
• Reported high-speed single-channel testing and real-time array operation.

Conclusions:

• The developed photonic chip serves as an effective interface for parallel-accessed optical bit-plane data.
• This represents the first smart-pixel array with vertical integration of quantum-well modulators/detectors over active silicon VLSI.
• The device offers over 340 transistors per optical input-output, enabling advanced functionalities.