Variable optical true-time delay line breaking bandwidth-delay constraints.

Area of Science:

• Photonics and Optical Engineering
• Integrated Optics
• Signal Processing

Background:

• Traditional optical delay lines face bandwidth-delay product limitations, restricting their application scope.
• Ring resonator-based solutions offer limited bandwidth and control.
• True-time optical delay lines are crucial for advanced optical systems.

Purpose of the Study:

• To propose and demonstrate an integrated optical delay line architecture that overcomes the bandwidth-delay product constraint.
• To present a scalable solution for variable true-time optical delays.
• To offer an alternative to existing ring resonator-based delay lines.

Main Methods:

• Development of an integrated topology using multiple parallel Mach-Zehnder Interferometers (MZIs).
• Experimental demonstration using a 4-stage delay line.
• Characterization through time and frequency domain measurements.

Main Results:

• The proposed device successfully breaks the bandwidth-delay product limit.
• A 4-stage delay line achieved 90 ps delay over a 22 GHz bandwidth.
• Negligible group delay distortion and a wide operational wavelength range of ~60 nm were observed.
• The architecture demonstrates scalability for increased MZI stages.

Conclusions:

• The novel MZI-based integrated topology provides a scalable solution for true-time optical delay lines.
• This approach significantly enhances bandwidth and control compared to previous methods.
• The demonstrated performance validates the potential for advanced optical signal processing applications.