A tunable Vernier fiber Fabry-Perot filter for FDM demultiplexing and detection

Abstract
An N-channel optical frequency-division multiplexing (FDM) network can be realized using frequency-shift keying (FSK) modulation and a tunable filter to select and detect the channels. A tandem arrangement of two fiber Fabry-Perot (FFP) filters is demonstrated. For FFPs with individual finesse (F) of 57 an effective finesse of 675 is obtained in a tandem arrangement. This has a capacity of N=F/3=225 channels in a frequency-division multiaccess (FDMA)-FSK network.<>