Patent ID: 6937809

Claim:
An optical device comprising: a first grin lens to receive a multiplexed signal having channel signals up to N respective wavelengths λ 1 λ 2 . . . λ N ; an optical filter mounted with the first grin lens to bounce off all of the channel signals with the wavelengths λ 1 λ 2 . . . λ N except for a signal with a wavelength λ i , wherein i is inclusively between 1 and N, the optical filter has a bandpass frequency profile centered at λ i . a variable neutral density filter; a first mirror receiving the signal with the wavelength λ i and reflecting the signal to the variable neutral density filler to be attenuated according to a desired level; a second grin lens; a second mirror receiving the attenuated signal from the variable neutral density filter and reflecting to the second grin lens that in turn outputs the attenuated signal.