Double tunable micro-ring enhanced Fourier transform spectrometer

It is a tradeoff between bandwidth and resolution for the on chip Fourier transform spectrometer. To solve this problem, a single ring filter enhanced on chip Fourier transform spectrometer was proposed recently. In this paper, the performance of the cascaded double-ring enhanced Fourier transform on chip spectrometer was investigated theoretically. The cascaded two tunable Micro-ring resonators forms a large narrow band filter with a larger free spectral range (FSR) than the single ring, which reduces the requirement of the Fourier transform spectrometer spectral resolution. The spectrum of the input is retrieved by the Fourier transform algorithm with dispersion correction. The cascaded doublering enhanced Fourier transform spectrometer has a high resolution (0.3 nm) and a large bandwidth (1500nm-1600nm). The fabrication process is compatibility with CMOS process. It can be easily integrated with other silicon-based optical devices.