DFB fiber lasers as optical wavelength standards in the 1.5-μm region

A single-mode distributed feedback (DFB) fiber laser has been frequency locked to a CO/sub 2/ absorption line at 1578.665 nm to demonstrate its potential as a wavelength standard. A frequency stability of 10/sup -8/ (/spl ap/2 MHz) was achieved on a time scale of minutes. A mechanical lead screw provided coarse wavelength tuning, white wavelength modulation and fast frequency corrections were applied by straining the fiber laser with piezoelectric transducers. With a suitable choice of absorption line, such a system may serve as an absolute frequency reference for dense wavelength-division multiplexing grids in telecommunication.