WDM Fiber-Optic True Time-Delay using Multi-Wavelength Source

B.-M. Jung, J.-D. Shin, and B.-G. Kim (Korea)


Phased array antenna, True time-delay, Fiber-optic delay lines, Beamformer, and Optical MEMS switch.


In this paper, we have proposed a wavelength-division multiplexing (WDM) fiber-optic true time-delay (TTD) beamformer for phased array antenna systems, and demonstrated a WDM 3-b TTD for a linear 10-GHz PAA with four antenna elements. It is composed of a 4×3 delay lines matrix and a multi-wavelength source with four discrete distributed-feedback (DFB) laser diodes. The building block of the delay lines matrix is a 2×2 optical MEMS switch with a proper length of fiber delay line connected between cross ports. The unit time delay difference used was 12 ps. The time delay error was measured to be less than ± 2 ps at six different RF frequencies from 5- to 10-GHz. The fabricated WDM TTD shows true time-delay characteristics in both domain of the RF frequency and the optical wavelength.

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