Tm-doped fiber amplifier utilizing wavelength conditioning for broadband performance

A multi-stage optical amplifier for operation at an eye-safe input optical signal wavelength λS within the 2 μm wavelength region, comprising:

• a plurality of N sections of single-clad Tm-doped optical fiber disposed in a concatenated configuration, each section defining a separate stage of the multi-stage optical amplifier, wherein an input optical signal is coupled into a first, input amplifier stage of the multi-stage optical amplifier and an amplified output signal exits from a last, output amplifier stage of the multi-stage optical amplifier;
• a pump source providing a pump beam to each separate amplifier stage of the multi-stage optical amplifier;
• and
• a wavelength conditioning element disposed along a signal path at an input to another amplifier stage of the multi-stage optical amplifier, the wavelength conditioning element responsive to an intermediate amplified optical signal and configured to normalize a gain profile and an output power density of the intermediate amplifier signal across a predetermined wavelength region, increasing an operating bandwidth of the intermediate amplified optical signal prior to propagating through the last, output amplifier stage of the multi-stage optical amplifier.