Quadrupling Optical Delay Range Using Polarization Properties

We describe a scheme to quadruple an optical delay using polarization properties of light in a fiber and demonstrate a fast variable delay line with a record-setting delay range of 72 mm at a speed of ~ 2 kHz (corresponding to ~ 136 m/s). The method can find various applications where a large optical delay or a high-speed delay variation is required, including optical coherent tomography, optoelectronic oscillator, programmable optical delay lines, and optical delay buffers.