2.3 W, Linearly-Polarized Superfluorescent Generation From a Polarization-Maintaining Er3+-Doped Fluoride Fiber Amplifier Around 2.8 μm

We present a high-power, polarization-maintaining (PM) Er ³⁺ -doped fluoride fiber amplifier, which enables watt- level, linearly-polarized (LP) superfluorescent outputs around 2.8 μm by using a non-PM Er ³⁺ -doped fluoride fiber superfluorescent source (FSS) after polarization controlling as the seed. Based on an optimized scheme, the gained superfluorescent signal with a 20 dB bandwidth of 95 nm (2710∼2805 nm) can yield a maximum power of 2.32 W and a polarization extinction ratio (PER) of up to ∼23.6 dB. To our knowledge, this is the first demonstration of a mid-infrared (mid-IR) PM fiber amplifier, and the power also represents, until now, the highest level from a FSS in the mid-IR. Further power scaling is only limited by the seed power, and can be anticipated by boosting seed power or/and adopting multi-stage amplification. This work provides an alternative way for high-power, LP, mid-IR FSS, enabling a range of real-world applications.