Honeycomb Photonic Bandgap Fiber With a Modified Core Design

Air-silica honeycomb fiber with a modified core design is introduced. The core has a concentrated high-index region. Such core design helps defect core mode stay in the cladding's photonic bandgap for a longer wavelength range (>1000 nm) as compared to conventional design. We further point out the importance of our core design in reducing the number of defect modes supported by the fiber structure.