Two optical fibers with different types of air-hole imbedded structures were serially concatenated to provide novel transmission characteristics. Bending sensitive shifts of the fundamental mode cutoff in a hollow optical fiber and a hexagonal microstructured holey fiber were found to be in opposite directions, which defines a new window with flexible tuning of the center wavelength and the bandwidth of transmission by independent bending radii control of the fibers. The concatenated composite structure provided useful optical transmission window management ranging from $400\text{to}1700\mathrm{nm}$ along with a tunable pass bandwidth of $300–1000\mathrm{nm}$ and a sideband rejection efficiency better than $20\mathrm{dB}$ .