On-chip microwave photonic beamformer circuits operating with phase modulation and direct detection

Area of Science:

• Photonics and Microwave Engineering
• Integrated Optics
• Signal Processing

Background:

• Microwave photonic (MWP) beamformers are crucial for advanced wireless communication systems.
• Existing MWP beamformers often require complex modulators and detectors, increasing cost and reducing stability.
• Phase modulation (PM) and direct detection (DD) offer potential for simplified MWP systems.

Purpose of the Study:

• To propose and demonstrate novel MWP beamformer circuits utilizing phase modulation (PM) and direct detection (DD).
• To integrate broadband beamforming networks and optical sideband manipulators for enhanced functionality.
• To achieve low-circuit-complexity modulators and detectors for improved system cost and stability.

Main Methods:

• Design and fabrication of two novel MWP beamformer circuits using Si(3)N(4)/SiO(2) waveguide technology.
• Incorporation of ring resonator-based delay lines for broadband beamforming.
• Implementation of an optical sideband manipulator to emulate intensity modulation outputs.

Main Results:

• Experimental verification of the proposed MWP beamformer circuits' working principles.
• Demonstration of a 2 × 1 beamforming effect within an instantaneous RF transmission band of 3–7 GHz.
• Successful integration of PM and DD functionalities in on-chip MWP beamformer circuits.

Conclusions:

• The proposed MWP beamformer circuits effectively combine broadband beamforming and optical sideband manipulation.
• The use of PM and DD with simplified components leads to significant benefits in system cost and operational stability.
• This work represents the first experimental verification of on-chip MWP beamformer circuits operating with PM and DD.