SOI based ultracompact polarization insensitive filter for PDM signal processing.

Area of Science:

• Photonics and Optical Engineering
• Integrated Optics
• Signal Processing

Background:

• Polarization division multiplexing (PDM) is crucial for high-capacity optical communication.
• Existing devices for PDM signal processing often suffer from polarization sensitivity.
• Efficient and robust demodulation techniques are needed for advanced optical networks.

Purpose of the Study:

• To propose and demonstrate a novel polarization-insensitive device for PDM signal processing.
• To integrate a 2D grating coupler with a delay interferometer in a loop configuration.
• To achieve successful demodulation of PDM signals with high performance.

Main Methods:

• Fabrication of a device combining a 2D grating coupler and a delay interferometer (DI) in a loop.
• Utilizing the 2D grating coupler to split and combine optical signals based on polarization states.
• Implementing a common DI for copropagating signals within the loop.
• Demonstrating the device's performance using PDM non-return-to-zero differential-phase-shift-keying (NRZ-DPSK) signals.

Main Results:

• The proposed device exhibits polarization insensitivity.
• Successful demodulation of PDM NRZ-DPSK signals was achieved.
• Bit error ratio (BER) measurements confirmed error-free operation.
• The device demonstrated good performance and practicability.

Conclusions:

• The integrated 2D grating coupler and DI loop configuration offers a robust solution for PDM signal processing.
• The polarization-insensitive nature of the device enhances its applicability in optical communication systems.
• The demonstrated error-free operation validates the device's potential for practical implementation.