Simplified model of an FSK-to-ASK direct-detection system using a Fabry-Perot demodulator

Design guidelines are presented for a direct-detection optical transmission system in which an FSK (frequency-shift-keyed) signal is converted to ASK (amplitude-shift-keyed format) by a tunable Fabry-Perot filter demodulator/demultiplexer. The analysis gives an estimated set of conditions for the proper Fabry-Periot (FP) bandwidth and tone frequency deviation that reduces the system power penalities. This is accomplished by calculating the tonal power transmitted through the FP; this simplifying assumption neglects pattern dependences but provides a simple, useful expression for predicting regions of rapidly increasing power penalties. The generated curves agree well with experimental results for three different systems.<
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