Subpicometer accuracy laser wavelength sensor using multiplexed Bragg gratings

Wavelength- and angle-multiplexed holographic Bragg gratings are used as a highly sensitive wavelength sensor. An absolute wavelength accuracy as high as 0.3 pm has been demonstrated with gratings recorded in an Fe-doped LiNbO/sub 3/ photorefractive crystals of dimension of 5/spl times/5/spl times/4 (mm/sup 3/). This technique provides a simple and accurate solution to laser wavelength measurement in applications such as wavelength division multiplexed (WDM) fiber-optic networks, precision interferometry, Doppler spectroscopy, and others.