High-speed waveguide photodetector for 64  Gbaud coherent receiver

Area of Science:

• Photonics and Optoelectronics
• Integrated Optics
• Semiconductor Devices

Background:

• Integrated coherent receivers are crucial for high-capacity optical communication systems.
• Waveguide photodetectors are key components in these receivers, requiring high speed and low loss.
• Existing photodetectors face challenges in achieving optimal performance for advanced modulation formats.

Purpose of the Study:

• To design and fabricate a high-speed waveguide photodetector for 64 Gbaud integrated coherent receivers.
• To optimize the device for high responsivity and low polarization-dependent loss.
• To enhance electrical properties for improved high-speed operation.

Main Methods:

• Fabrication of a waveguide photodetector with dual laterally tapered spot-size converters.
• Optimization of optical and electrical properties using beam propagation method simulation.
• Adjustment of matching layer thickness and n-doped upper taper for enhanced performance.

Main Results:

• Achieved high responsivity of 0.73 A/W and low polarization-dependent loss of 0.27 dB.
• Demonstrated a 3 dB bandwidth of 45 GHz for high-speed operation.
• Experimental results closely matched simulation predictions.

Conclusions:

• The developed waveguide photodetector meets the stringent requirements for 64 Gbaud integrated coherent receivers.
• The design incorporating spot-size converters offers excellent optical and electrical performance.
• This work contributes to the advancement of high-speed optical communication technologies.