Patent ID: 6795188
Filing Date: 2004-09-21
Classification: G01J

Abstract:
A wavemeter for determining a wavelength of an incoming optical beam comprising:a coarse-measuring unit for determining in a first wavelength range and with a first accuracy, a first wavelength value as representing the wavelength of the incoming optical beam, a fine-measuring unit for providing a wavelength determination with a second accuracy for the incoming optical beam, wherein the wavelength determination is ambiguous within the first wavelength range but unambiguous in each of a plurality of unambiguous wavelength ranges, so that a plurality of different wavelength values correspond to a measuring value as measured by the fine-measuring unit for the incoming optical beam and wherein the second accuracy is higher than the first accuracy, an evaluation unit for determining a second wavelength range covering the first wavelength value, and for determining a second wavelength value as the one of the plurality of different wavelength values that corresponds to the measuring value in the second wavelength range, and output means for providing the second wavelength value as a measuring result of the wavemeter representing the wavelength of the incoming optical beam, wherein the coarse-measuring unit comprises a beam splitter adapted for splitting up a received beam derived from the incoming optical beam into a first beam towards a first detector and a second beam directed towards a second detector, and wherein the beam splitter provides a coupling-ratio between the first and second beams which is dependent on the wavelength of the received optical beam.