Abstract: A universal inline functional module for operation with nonzero average gain G?0 dB over a bandwidth is provided. The module includes at least one optical functional element producing loss over the bandwidth and at least one rare-earth doped fiber segment. The module produces a flat gain spectrum to within a specified tolerance when made to operate at an average gain of 0 dB over the bandwidth.

Abstract: A universal inline functional module for operation with nonzero average gain G?0dB over a bandwidth is provided. The module includes at least one optical functional element producing loss over the bandwidth and at least one rare-earth doped fiber segment. The module produces a flat gain spectrum to within a specified tolerance when made to operate at an average gain of 0 dB over the bandwidth.

Abstract: A method for increasing the number of channels amplified by an optical amplifier arrangement is provided. The optical amplifier arrangement includes at least one optical amplifier stage amplifying a first number of channels at a given average gain level. The method begins by selecting a second number of channels to be amplified by the optical amplifier arrangement. At least one additional optical amplifier stage is serially coupled to an input or output of the at least one optical amplifier stage to form a multistage optical amplifier arrangement. The gain shape of the multistage optical amplifier is adjusted to maintain, at the given average gain level or greater, a prescribed degree of gain flatness over an operating bandwidth in which the second number of channels are located.