Patent ID: 7499175

Claim:
An interferometer with wavelength blockage based on a predetermined wavelength, the interferometer comprising: a beamsplitter that splits an incoming signal into a first sub-signal and a second sub-signal; a first plate through which the first sub-signal passes, the first plate having a refractive index n and a thickness t, and being disposed perpendicular to a direction in which the first sub-signal travels; a first mirror that receives the first sub-signal from the first plate and directs the first sub-signal back through the first plate to the beamsplitter; a second plate through which the second sub-signal passes, the second plate having a refractive index n and a thickness t, and being disposed at an angle θ to a direction in which the second sub-signal travels; and a second mirror that receives the second sub-signal from the second plate and that directs the second sub-signal back through the second plate to the beamsplitter where the first sub-signal and the second sub-signal are combined to form an output signal, the output signal having a range of wavelengths with attenuated amplitudes; wherein one of the first mirror and the second mirror is a moveable mirror that adjusts an optical path length of a respective one of the first sub-signal and the second sub-signal to introduce an optical path difference (“OPD”) between the optical path lengths of the first sub-signal and the second sub-signal.