Distortion-free spectrum sliced microwave photonic signal processor: analysis, design and implementation

Area of Science:

• Photonics
• Microwave Engineering
• Signal Processing

Background:

• Microwave photonic filters (MPFs) are crucial for advanced signal processing.
• Existing MPFs face challenges with tunability, reconfigurability, and radio frequency (RF) degradation.

Purpose of the Study:

• To introduce a novel switchable microwave photonic filter using spectrum slicing.
• To enable programmable multi-tap generation with general transfer function characteristics.
• To compensate for dispersion-induced RF degradation within a single device.

Main Methods:

• A dispersion-controlled spectrum slicing filter is connected after a modulated bipolar broadband light source.
• Multiple spectrum slices with bipolarity are generated, simultaneously compensating for dispersion.
• A detailed theoretical model is developed and experimentally verified.

Main Results:

• A 33 bipolar-tap microwave filter was demonstrated with reduced high-frequency passband attenuation.
• The filter shows effectiveness for various free spectral ranges and spectrum slice bandwidths.
• A switchable bipolar filter with a square-top bandpass response and >30 dB stopband attenuation was achieved.

Conclusions:

• The novel spectrum slicing technique provides a versatile platform for switchable microwave photonic filters.
• The demonstrated filter offers significant improvements in RF response and programmability.
• Software control enables on/off switching, enhancing practical applicability.