Continuously-tunable microwave photonic true-time-delay based on a fiber-coupled beam deflector and diffraction...

Area of Science:

• Microwave Photonics
• Optical Communications
• Signal Processing

Background:

• Accurate phase control is crucial for high-performance microwave photonics and optical communication systems.
• Existing true-time delay lines often lack continuous tunability or sufficient phase resolution.
• The demand for wider modulation bandwidths necessitates novel delay line solutions.

Purpose of the Study:

• To demonstrate a continuously-tunable true-time delay line for microwave photonics.
• To achieve high-resolution phase control over a broad modulation frequency range.
• To evaluate the device's performance metrics, including delay tuning range, insertion loss, and signal variation.

Main Methods:

• Development and characterization of a fiber-coupled tunable true-time delay line device.
• Utilizing microwave photonics principles for signal manipulation.
• Experimental measurement of delay tuning range, optical insertion loss, RF amplitude/phase variation, and delay ripple.

Main Results:

• Demonstrated a fiber-coupled device with a 75 ps continuous delay tuning range.
• Achieved a low optical insertion loss of 3 dB.
• Observed minimal RF amplitude and phase variation within the 4-18 GHz band.
• Measured delay ripple below 0.2 ps, indicating high precision.

Conclusions:

• The demonstrated device offers a significant advancement in tunable true-time delay lines for optical communications.
• The device exhibits excellent performance characteristics, including high resolution and low signal distortion.
• Theoretical analysis suggests scalability to much larger delay tuning ranges and modulation bandwidths, paving the way for future applications.