Compact 1625-nm Noncritically Phase-Matched ${\rm KTiOPO}_{4}$ Optical Parametric Oscillator Intracavity Driven by the ${\rm KTiOAsO}_{4}$ Raman Laser

Raman lasers offer great potential for efficiently pumping optical parametric oscillation (OPO) and achieving parametric radiations with high beam quality. Compact noncritically phase-matched 1625-nm KTiOPO
₄
(KTP) OPO intracavity driven by the 1091-nm KTiOAsO
₄
(KTA) Raman laser is demonstrated. The maximum average output power at the signal wavelength of 1625 nm is 180 mW obtained under the LD pump power of 8 W. Corresponding pulse repetition rate and pulse width are, respectively, measured to be 8 kHz and 2.1 ns, with the single pulse energy and peak power calculated to be 22.5 μJ and 10.7 kW, respectively. The
M
²
factor of the signal wave is measured to be 1.3 by knife-edge technique. The cascaded Raman conversion in KTA and OPO in KTP may provide a new method for obtaining 1625-nm laser with high beam quality, a potential light source for optical time-domain reflectometer.