Bias-free high-dynamic-range phase-modulated fiber-optic link

Bias-free optical phase demodulation using an optical delay line filter is analyzed and experimentally demonstrated. A spur-free dynamic range of 114 dB/Hz/sup 2/3/ is measured at a frequency of 12.5 GHz using optical carrier suppression. The method is shown to have the same dynamic range, noise figure, and link gain compared to a Mach-Zehnder link over a limited bandwidth.