Patent ID: 6498800
Filing Date: 2002-12-24
Classification: G01J,H01S

Abstract:
A wavelength reference apparatus for use in calibrating light output from a tunable optical device to a precise, absolute frequency on a target frequency grid, the wavelength reference apparatus comprising:a beam splitter; a light pathway extending between the optical device and the beam splitter; a first etalon configured to receive light from the beam splitter, wherein the first etalon is chosen so as to have its transmission peaks spaced at the target frequency grid; a first detector for detecting the transmission peaks established by the first etalon; a dielectric filter and a second etalon configured to receive light from the beam splitter, wherein the dielectric filter is chosen so as to have its transmission peak centered on a peak in the target frequency grid and the second etalon is chosen so as to have its transmission peaks spaced significantly further apart than the target frequency grid; and a second detector for detecting a transmission peak established by the dielectric filter in series with the second etalon; whereby when monotonic light from the tunable optical device is swept into the light pathway and through the apparatus, the transmission peak established by the dielectric filter and the second etalon will identify a specific frequency on the target frequency grid that corresponds to the wavelength of the monotonic light provided by the tunable optical device.