All-fiber WDM optical crossconnect using ultrastrong widely tunable FBGs

In this letter, we demonstrate an all-fiber wavelength-division-multiplexed optical crossconnect using ultrastrong fiber Bragg gratings (FBGs) with wi de tunability. These FBGs have 0.2-nm bandwidths and can be tuned over simi lar to 52 nm due to a novel grating preparation technique to reduce mechani cal strength degradation. There is negligible distortion in the transmissio n spectra while tuning the grating, and the crossconnect architecture uses cascades of these gratings for WDM operation. The ability to tune these > 9 8% reflectivity gratings completely out of the entire WDM signal band minim izes the leakage of unwanted signal power and leads to the improvements of > 10-dB crosstalk and >0.6-dB power penalty compared with conventional grat ings.