Energy-efficient optical access networks supported by a noise-powered extender box

A method for energy-efficient amplification by reutilization of optical noise as pumping power in access networks with extended loss budget is presented. The amplified spontaneous emission (ASE) of an optical amplifier at the customer premises is thereby reshaped and reused as a natural pump source for Erbium-doped fibers (EDF) inside the signal distribution elements of an access network. This increases the number of served customers and enables also transmission at no extra cost, by just recycling optical noise. Three scenarios, which differ in the design of the optical network unit (ONU), are evaluated and show that up to 4000 users can be served in passive optical networks with adequate signal quality for certain configurations of the ONU. Typical transmission constraints due to the use of cost-effective reflective ONUs, such as Rayleigh backscattering effects, are reduced due to the introduction of a distributed amplification scheme. Besides, full-duplex 10 Gb/s transmission on a single wavelength with simultaneous EDF pump generation is demonstrated with low-cost ONUs, based on reflective semiconductor optical amplifiers. A comparison with traditional amplification techniques is given, and the relationship between the different power consumption for the pump delivery is discussed