Abstract

Photonic true-time-delay (TTD) networks for microwave antenna applications have been investigated in recent years.^1–4 These networks are a hybrid of optical fibers and switching elements,¹ a circuit composed of dispersive prisms and a tunable laser,² or a hybrid circuit of integrated delay lines routing in the electrical domain.³ The authors have developed a fully integrated controllable TTD network using silica-based planar lightwave circuits (PLCs),⁴ which have the characteristics of low loss (0.1 dB/cm or less), far easier polarization maintenance, patterning flexibility (the minimum radius is 2 mm when Δ is 1.5%), and active circuit capability through the thermo-optic effect.⁵

© 1996 Optical Society of America