Patent ID: 8170384

Claim:
A variable fiber optic delay line comprising: a tunable laser to produce a variable laser input beam for wavelength tuning; an input circuit including an electro-optic modulator for receiving and electrically modulating the laser input beam; a switchless discrete long time delay module to receive the modulated laser beam, the switchless discrete long delay module including intrinsic variable attenuation coupled with the input circuit, the discrete long delay module including a wavelength division multiplexing coupled fiber array delay line for flat-top passband type multiplexing of the modulated laser beam, the fiber array delay line having a predesigned bias delay for injecting a first time delay into a modulated laser beam to produce a first delayed output signal; a switchless analog variable short delay module for receiving the first delayed output signal from the switchless discrete long time delay module and injecting a second time delay that is shorter than the first time delay to produce a delayed output signal having a delay approximately equal to the first time delay plus the second time delay; and an optical detector to detect the delayed optical signal and produce a corresponding delayed electrical signal, wherein the delay of the electrical signal is selected by tuning the tunable laser to match one channel of the fiber array delay line to produce a preselected delay of the delayed electrical signal.