Patent ID: 7880968

Claim:
An optical filter comprising a Michelson interferometer or a Mach-Zehnder interferometer having a first optical path length L 1 and a second optical path length L 2 , the Michelson interferometer or the Mach-Zehnder interferometer further having a plurality of Gires-Tournois interferometers (“GTIs”) replacing a plurality of minors of the Michelson interferometer or the Mach-Zehnder interferometer, a first one of the plurality of GTIs having a first GTI spacing d 1 , a second one of the plurality of GTIs having a second GTI spacing d 2 , and an optical path difference ΔL=L 1 −L 2 , wherein Δ L= (2 n M −1)(λ target 1 /2) or Δ L= 2 n M (λ target 1 /2), d 1 =2 n GTI 1 (λ target 1 /4), and d 2 =0, wherein λ target 1 is a target wavelength, n M is an integer greater than zero, and n GTI 1 is an integer greater than zero.