Patent ID: 7133136

Claim:
A wavelength monitoring device for monitoring a beam of light, comprising: a) a beam splitter, having opposing first and second spaced apart faces, for receiving optical radiation from the beam of light to be monitored, one of the first and second faces for reflecting a first portion of the optical radiation to a first location, the other of the first and second faces including an optical structure thereon or thereabout for reflecting: a second portion of the optical radiation to the first location, a third portion of optical radiation to the second location, b) a first photodiode disposed to receive optical radiation present at the first location after the first portion and the second portion of optical radiation have optically interfered to form a composite beam, the first photodiode for detecting a wavelength characteristic of the composite beam; and, c) a second photodiode disposed to receive the optical radiation present at the second location, wherein the third portion of optical radiation at the second location corresponds proportionally to optical power of the incident beam of light; wherein the first face and optical structure are oriented and spaced from one another so that the first and second portions of the optical radiation optically interfere with one another along a path toward the first photodiode.