Abstract: An optical fiber comprising a core having a refractive index profile and a centerline; and a cladding layer surrounding and directly adjacent the core; wherein core includes updoping material and is doped with Aluminum in at least one region of the core, such that either: (a) the average longitudinal acoustic wave velocity within the core is within 0.05% of the longitudinal acoustic wave velocity within the cladding; or (b) the longitudinal acoustic wave velocity in the core changes by at least 0.2%.

Abstract: A module for use in a passive optical network including a single coil of erbium and a passive optical splitter, whereby digital and analog signals pass through the module from a central office/head end and a subscriber premise, while only the analog signal passes through the single coil of erbium for signal amplification.

Abstract: An apparatus for multiple signal amplification in a passive optical network, includes a remotely-pumped, single erbium coil positioned intermediate a central office and a split point in the network, wherein both analog and digital signals transmitted within an erbium coil amplification band from the central office and one or more subscriber premises pass through the erbium coil and are amplified prior to being split at the split point.