Real-time wavelength routing based on Bragg reflection with integrated forward Raman for long-reach networks

Abstract

We experimentally demonstrate the all-optical efficient technique for dynamic full-duplex wavelength routing and reach extension through adoption of passive fibre Bragg grating (FBG), energy efficient vertical cavity surface emitting lasers (VCSELs) and high gain forward Raman pump. In this study, two VCSEL channels at 1 549.62 nm and 1 550.01 nm are directly modulated with a 8.5 Gbit/s data signal each, and transmitted over 25.5 km fibre to a passive single mode FBG-based wavelength routing node. The precise wavelength selectivity of the FBG is exploited to achieve all-optical real-time wavelength routing of the 1 549.62 nm VCSEL channel with a maximum insertion loss of 22.1 dB. The 1 550.01 nm channel is transmitted through the FBG with a maximum penalty of 1.03 dB. By utilizing the 7.2 dB flat gain of a forward Raman pump, the routed 1 549.62 nm VCSEL channel is transmitted over 76.7 km fibre with a maximum penalty of 3.84 dB at bit error rate (BER) of 5−5. Our technique is all-optical, power efficient as it employs passive FBG and circulators and has low cross talk allied to precise wavelength selectivity of the technique.