Tunable Optical OFDM Demultiplexer Utilizing Slab Star Coupler-Based Optical DFT Circuit

We report on a tunable integrated-optic circuit for demultiplexing optical orthogonal frequency division multiplexing (OFDM) signals with various number of sub-carrier channels. The demultiplexer is composed of tunable optical discrete Fourier transform filter (tunable couplers, delay lines, and a slab star coupler) and optical gates. Various sub-carrier number optical OFDM signals can be demultiplexed by selecting the active delay lines with the tunable couplers. After explaining the demultiplexer and its operating principle, we show some experimental results including transmittance and bit error rate measurement of demultiplexed sub-carriers from various sub-carrier number optical OFDM signals. 2 × 10 Gbit/s to 10 × 10$ Gbit/s OFDM signals could be successfully demultiplexed.