$1\text{−}\mu m$ laser with natural phase matching based on a monolithic box resonator

Optical parametric oscillation based on a monolithic resonator is an important way to generate a coherent laser with a narrow linewidth and a wide tunable range in a long wavelength, which can be used in spectroscopy and quantum source generation. In this Letter, we demonstrate doubly resonant optical parametric oscillation with natural phase matching based on the box resonator with $Q$ up to $5.68\times {10}^7$. Moreover, we realized a $1\text{−}\mu m$ laser with a 1-kHz linewidth, a 200-mW output power, and a 153.94-nm wavelength tuning range. Furthermore, the monolithic box resonator has the potential to achieve a fully integrated high-power laser, and it can also be used for highly efficient spontaneous parametric down-conversion and bright narrow-band biphoton generation.