Abstract

A novel design of a tunable True-Time delay line (TTDL) based on a multicore photonic crystal fiber (PCF) is proposed. It enables simultaneous transport and processing of microwave photonic signals over a broad radiofrequency processing range. Independent group delay behavior in 19 different cores characterized by a constant differential group delay between cores provides TTDL operation on 19 signal samples. The 19-core PCF structure allows tailoring the chromatic dispersion range between 1.5 and 31.2 ps/nm·km, which translates into a very broad microwave signal processing range from a few up to tens of GHz. A near-zero dispersion slope reduces the time delay errors in the TTDL's operation to less than 5% in a 40-nm optical wavelength range, thus ensuring its satisfactory performance. Its performance as a TTDL is evaluated in terms of higher-order dispersion as well as other degradation effects such as crosstalk and nonlinear fiber response. A high index contrast between core and cladding, between 0.3 to 1.5%, enables low intercore crosstalk and confinement losses as well as greater robustness against fiber bends and twists. Fabrication of this type of MCF might be possible although it will prove challenging. This work advances the state-of-the-art of a TTDL based on SDM technology by increasing the number of samples and microwave processing range.

Design of heterogeneous multicore fibers as sampled true-time delay lines

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Ring-core few-mode fiber for tunable true time delay line operation

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Dispersion-engineered multicore fibers for distributed radiofrequency signal processing

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Sampled true time delay line operation by inscription of long period gratings in few-mode fibers

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Few-mode fiber true time delay lines for distributed radiofrequency signal processing

Rubén Guillem, Sergi García, Javier Madrigal, David Barrera, and Ivana Gasulla
Opt. Express 26(20) 25761-25768 (2018)