We report experimental results on an efficient singly resonant optical parametric oscillator (OPO) based on periodically poled MgO-doped LiNbO3. The OPO was pumped by a diode-pumped passively Q-switched Nd:GdVO4 laser, which could produce 3-ns laser pulses with a repetition rate of 5 kHz. By changing the crystal temperature and grating periods, the OPO generated signal and idler output in the ranges of 1.41 to 1.78 µm and 2.7 to 4.3 µm, respectively. The maximum output power at the signal wavelength of 1.55 µm was 35.4 mW with 120-mW pump power. The possibility of using the OPO for trace gas detection was demonstrated through measuring the absorption spectra of methane.
We report on the use of the temperature-tuned optical parametric oscillator for trace gas detection. A synchronization trace gas detection system was designed and demonstrated, in which the measuring errors caused by the instability of the OPO could be greatly reduced. The trace gas detection system was based on a periodically poled MgO-doped LiNbO3 optical parametric oscillator (OPO) which was pumped by a diode-pumped passively Q-switched Nd:GdVO4 laser. The OPO could produce wavelength-tunable signal output through changing the crystal temperature and the grating periods. The usefulness of the trace gas detection system for spectroscopy was demonstrated by directly measuring the photon absorption spectrum of the methane and acetylene gas cells.
We have experimentally investigated the soliton interaction in a passively mode-locked fiber soliton ring laser and revealed the existence of three types of strong soliton interaction: a global type of soliton interaction caused by the existence of unstable CW components; a long-range type of soliton interaction mediated through the radiative dispersive waves; and the direct soliton interaction. Based on the soliton interactions we found that the appearance of the various soliton operation modes observed in the passively mode locked fiber soliton lasers could be well explained. Numerical simulations have also confirmed the existence of these soliton interactions and their consequences.
We demonstrate experimentally a novel form of double-pulse solitary waves in a passively mode-locked fiber ring laser. The new solitons are characterized as that they consist oftwo single solitons with fixed, discrete pulse separations. Through studying the interaction between bound-soliton pairs observed in a passively mode4ocked fiber laser, we firstly revealed that the bound soliton pair behaves as a unit, and has exactly the same interaction properties as those of the single pulse soliton in the laser. Numerical simulations confirm the existence of the new form of solitons in the laser.