Differential phase-shift-keying demodulation by coherent perfect absorption in silicon photonics

Area of Science:

• Photonics
• Integrated optics
• Optical communications

Background:

• Differential phase-shift-keying (DPSK) is a key modulation format in optical communications.
• Efficient and compact demodulators are crucial for high-speed optical networks.
• Coherent perfect absorption (CPA) offers a promising mechanism for light manipulation.

Purpose of the Study:

• To demonstrate a novel DPSK demodulator utilizing CPA.
• To integrate essential components onto a single chip for miniaturization.
• To achieve high-speed passive operation at telecommunication wavelengths.

Main Methods:

• Design and fabrication of a silicon ring resonator with two bus waveguides.
• Integration of monolithically detectors for signal readout.
• Utilizing critical coupling by tuning the waveguide gap for efficient CPA.
• Characterization of device performance at 10 Gbps.

Main Results:

• Demonstration of a passive DPSK demodulator chip.
• Achieved operation at 10 Gbps bit rate.
• Device exhibits a vertical eye opening of 12.47 mV and a quality factor > 3x10^4.
• The device operates at telecommunication wavelengths within a mm-scale footprint.

Conclusions:

• The developed CPA-based DPSK demodulator is a novel and efficient solution.
• The compact and passive nature of the device makes it suitable for integrated photonic circuits.
• The underlying principle can be extended to other integrated demodulator formats.