Heterogeneous photodiodes on silicon nitride waveguides

Area of Science:

• Photonics
• Optoelectronics
• Materials Science

Background:

• Heterogeneous integration is crucial for advanced photonic circuits.
• Silicon nitride (Si3N4) offers a robust platform for photonic integration.
• III-V semiconductor materials are essential for high-performance optoelectronic devices.

Purpose of the Study:

• To demonstrate the integration of InGaAs/InP modified uni-traveling carrier photodiodes onto Si3N4 waveguides.
• To achieve high-performance photodetectors for optical communication applications.
• To evaluate the performance metrics including bandwidth, responsivity, and dark current.

Main Methods:

• Low-temperature die bonding for heterogeneous integration.
• Fabrication of InGaAs/InP modified uni-traveling carrier photodiodes.
• Integration of photodiodes with Si3N4 photonic waveguides.
• Characterization of photodiode performance at 1550 nm and 1064 nm.

Main Results:

• Demonstrated InGaAs/InP photodiodes on Si3N4 waveguides with 20 nA dark current.
• Achieved a 20 GHz bandwidth for individual photodiodes.
• Recorded record-high external responsivities of 0.8 A/W (1550 nm) and 0.33 A/W (1064 nm).
• Open eye diagrams confirmed successful operation at 40 Gbit/s.
• Balanced photodiodes achieved 10 GHz bandwidth with >40 dB common mode rejection ratio.

Conclusions:

• Low-temperature die bonding enables high-performance III-V photodetectors on Si3N4 photonic platforms.
• The demonstrated photodiodes show excellent performance for high-speed optical communication.
• This integration technique is promising for future silicon nitride-based photonic integrated circuits.