Two-mode multiplexing at 2 × 10.7 Gbps over a 7-cell hollow-core photonic bandgap fiber

Current technologies are fast approaching the capacity limit of single mode fibers (SMFs). Hollow-core photonic bandgap fibers (HC-PBGFs) are expected to provide attractive long-term solutions in terms of ultra-low fiber nonlinearities associated with the possibility of mode scaling, thus enabling mode division multiplexing (MDM). In this work, we demonstrate MDM over a HC-PBGF for the first time. Two 10.7 Gbps channels are simultaneously transmitted over two modes of a 30-m long 7-cell HC-PBGF. Bit error ratio (BER) performances below the FEC threshold limit (3.3 × 10(-3)) are shown for both data channels when the two modes are transmitted simultaneously. No power penalty and up to 3 dB power penalty at a BER of 10(-9) are measured for single mode transmission using the fundamental and the LP(11) mode, respectively. The performance of this exploratory demonstration is expected to improve significantly if advanced mode launching and detection methods are used.