Exploiting high-order phase-shift keying modulation and direct-detection in silicon photonic systems

Area of Science:

• Photonics
• Optical Communications
• Computational Modeling

Background:

• Silicon photonics offers efficient optical interconnects.
• High-order phase-shift keying (PSK) modulation is crucial for high-speed data transmission.
• Accurate bit-error ratio (BER) evaluation is essential for system performance optimization.

Purpose of the Study:

• To develop and apply a computational approach for evaluating BER in silicon photonic systems with high-order PSK modulation.
• To investigate the impact of various system parameters on BER.
• To analyze signal propagation through silicon waveguides and direct-detection receivers.

Main Methods:

• Utilized a modified nonlinear Schrödinger equation to model signal propagation in silicon waveguides, including linear and nonlinear optical effects.
• Incorporated free-carrier dynamics and their interaction with the optical field.
• Employed a frequency-domain approach based on the Karhunen-Loève series expansion for BER calculation.

Main Results:

• Identified optical power, PSK modulation type, waveguide length, and group-velocity as critical factors influencing BER.
• Demonstrated that nonlinearity significantly amplifies the impact of these factors on BER.
• Observed a substantial performance degradation in the slow-light regime, despite reduced interconnect lengths.

Conclusions:

• The computational method provides accurate BER evaluation for silicon photonic systems.
• System performance is highly sensitive to nonlinearity and operating in the slow-light regime.
• Design choices in silicon photonic interconnects must carefully balance nonlinearity and group-velocity effects for optimal PSK signal transmission.