30 W-class tunable single-frequency thulium-doped fiber amplifier at 1730–1762 nm with low intensity noise

We report a fully fibered, polarization-maintaining, single-frequency thulium-doped fiber amplifier operating between 1730 and 1762 nm and delivering more than 30 W of output power. Relative intensity noise is preserved after amplification, with a noise floor of -158 dBc/Hz between 100 kHz and 4 MHz. These results demonstrate the suitability of this source for quantum technology, including direct operation within the tuning range at 1762 nm for barium ion excitation or a possible nonlinear frequency conversion toward 813 nm for strontium atom trapping.