Long-wave infrared(IR) generation based on type-II(o→e+o) phase matching ZnGeP 2(ZGP) and CdSe optical parametric oscillators(OPOs) pumped by a 2.05 μm Tm,Ho:GdVO 4 laser is reported.The comparisons of the birefringent walk-off effect and the oscillation threshold between ZGP and CdSe OPOs are performed theoretically and experimentally.For the ZGP OPO,up to 419 mW output at 8.04 μm is obtained at the 8 kHz pump pulse repetition frequency(PRF) with a slope efficiency of 7.6%.This ZGP OPO can be continuously tuned from 7.8 to 8.5 μm.For the CdSe OPO,we demonstrate a 64 mW output at 8.9 μm with a single crystal 28 mm in length.
We report the demonstration of passively continuous-wave mode-locking(CWML) of diode-pumped Tm,Ho:YV04 laser using an InGaAs/GaAs multiple quantum-well(MQW) structure semiconductor as the saturable absorber.Stable mode-locking pulses at the central wavelength of 2 041 nm are obtained. The maximum output power is 151 mW.The pulse duration is 10.5 ps at the repetition rate of 64.3 MHz.
We present an all-fiber gain-switched thulium (Tm) doped fiber laser operating in the eye-safe region at 1940nm.The fibre Bragg gratings (FBGs) inscribed by phase mask technology are used as cavity mirrors,and the transmission spectra of FBGs are also measured.The output cbaracteristics are studied at pulse repetition frequene cies of 10,20 and 30kHz,and the maximum output powers of 28.9,67.0 and 71.0mW are achieved under incident pump powers of 122,247and 250mW.The narrowest pulse width of29ns and shortest pulse built-time of 140 ns are obtained at 10 kHz.The relation between pulse built-time and cavity length are discussed.
In this paper,the theoretical rate equation model of an in-band pumped gain-switched thulium-doped fiber(TDF) laser is investigated.The analytical formulations of pump energy threshold,peak power extraction efficiency,and pulse extraction efficiency are derived through analyzing the interaction process between the pump pulse and the laser pulse.They are useful for understanding,designing,and optimizing the in-band pumped TDF lasers in a 1.9 μm-2.1 μm wavelength region.The experiment with an all-fiber gain-switched TDF laser pumped by a 1.558-μm pulse amplifier is conducted,and our experimental results show good agreement with theoretical analysis.
