Patent ID: 7035505

Claim:
An optical apparatus for monitoring an input optical signal comprising: a dispersive element having M input ports and J output ports, wherein M>1 and J>1; control means disposed to receive the input optical signal for providing the input optical signal sequentially to each of the M input ports; and monitoring means optically coupled to the J output ports for monitoring one or more optical signals output therefrom for collecting information about the input optical signal at a plurality of K distinct optical frequencies, wherein K>max(J,M); wherein: the dispersive element couples an m th input port to a j th output port at an optical frequency f m,j for all integer values of m and j satisfying conditions 1≦j≦J and 1<m<M; a totality of the optical frequencies f m,j includes the plurality of K distinct optical frequencies; and |f m,j+1 −f m,j |≠|f m+1,j −f m,j |, wherein 1≦j≦(J−1) and 1≦m≦(M−1).