Cascaded resonant-grating filters: experimental results on lowered sidebands and narrowed lines

Cascaded resonant grating filters are experimentally characterized. The levels to which cascaded resonant filters yield lowered sidebands and narrowed linewidths, as compared with individual filters, are measured. For example, four cascaded filters provide experimental sideband levels at -47 dB over a 50-nm wavelength range, a spectral linewidth of 0.43 nm, with an insertion loss of 3.7 dB.