Opto-mechanical controlled variable RF/microwave delay element and method

摘要

A delay element and method for delaying an RF/microwave signal. The delay element uses a laser and an RF modulator to modulate a laser beam using an applied RF/microwave input signal. Collimating optics collimate the modulated laser beam and couple the beam to a delay element that controllably delays the modulated laser beam and hence the RF/microwave signal. The delay element has fixed retroreflectors, moveable retroreflectors disposed on a moveable armature or permanent magnet, and a coil disposed on a spring and coupled to the moveable armature. The beam is reflected multiple times between the fixed and multiple moveable retroreflectors. A dash pot may be used to suppress mechanical oscillation of the permanent magnet and moveable retroreflectors. A delay control current source supplies current to the coil to control movement of the moveable retroreflectors and thus the path length and delay experienced by the modulated laser beam. An RF detector detects and recovers the RF input signal to provide a delayed RF output signal from the delay element.