Tm ³⁺ –Tb ³⁺ ‐doped tunable fibre ring laser for 1700 nm wavelength region

Abstract

The first tunable fibre ring laser in the 1700 nm wavelength region has been developed. To achieve this fibre laser, a Tm 3+ –Tb 3+ ‐doped fibre is used as the active fibre, along with a tunable bandpass filter. A fibre ring laser that consisted of a 1.2/1.7 μm band wavelength division multiplexing coupler, a tunable bandpass filter, an active fibre and one 1.21 μm pump laser diode has been realised. A wide tuning wavelength band of 130.4 nm (from 1635.6 to 1766.0 nm) was achieved with a launched pump power of over ∼ 30 mW. The lasing threshold pump power at 1716 nm was ∼ 9 mW.