All-fiber WDM optical crossconnect using ultrastrong widely tunable FBGs

We demonstrate an all-fiber wavelength-division-multiplexed optical crossconnect using ultrastrong fiber Bragg gratings (FBGs) with wide tunability. These FBGs have 0.2-nm bandwidths and can be tuned over /spl sim/52 nm due to a novel grating preparation technique to reduce mechanical strength degradation. There is negligible distortion in the transmission spectra while tuning the grating, and the crossconnect architecture uses cascades of these gratings for WDM operation. The ability to tune these >98% reflectivity gratings completely out of the entire WDM signal band minimizes the leakage of unwanted signal power and leads to the improvements of >10-dB crosstalk and >0.6-dB power penalty compared with conventional gratings.