Tunable notch microwave photonic filter based on interferometry of a single low-incoherence source

Area of Science:

• Photonics
• Microwave Engineering
• Optical Signal Processing

Background:

• Microwave photonic filters (MPFs) are crucial for signal processing.
• Traditional notch MPFs using low-coherence interferometry often require multiple optical sources.
• Controlling and integrating multiple sources complicates system design.

Purpose of the Study:

• To propose and demonstrate a novel method for realizing a single-notch MPF.
• To simplify the implementation of notch MPFs by using a single broadband optical source.
• To achieve a tunable notch MPF with high performance.

Main Methods:

• Utilizing interferometry with a single, low-coherence broadband optical source (BOS).
• Implementing destructive interference between a bandpass and an all-pass MPF.
• Theoretical analysis and experimental validation of the proposed method.

Main Results:

• Successfully realized a single-notch MPF with a notch depth exceeding 30 dB.
• Demonstrated a continuously tunable frequency range from 2 to 18 GHz.
• Achieved freely tunable notch frequency and bandwidth.

Conclusions:

• The proposed method enables the realization of a single-notch MPF using a single BOS.
• This approach offers a simplified and flexible solution for tunable notch filtering.
• The experimental results confirm the viability and performance of the technique.