Broadband self-phased-locked degenerate continuous-wave optical parametric oscillator

Area of Science:

• Nonlinear Optics
• Laser Physics

Background:

• Continuous-wave (cw) optical parametric oscillators (OPOs) are crucial light sources in nonlinear optics.
• Achieving broadband and stable operation in degenerate OPOs remains a significant challenge.
• Phase-locking is essential for many advanced applications requiring coherent light.

Purpose of the Study:

• To demonstrate broadband self-phase-locked operation of a degenerate cw OPO.
• To investigate the impact of cavity dispersion control on phase-locking.
• To characterize the stability and output properties of the phase-locked OPO.

Main Methods:

• Utilized a degenerate cw OPO pumped by a 532 nm green laser.
• Employed a 10-mm-long MgO:PPLN crystal with a fan-out grating design.
• Controlled optical cavity dispersion to achieve self-phase-locking.
• Validated phase-locking using radio frequency and f-2f interferometric measurements.

Main Results:

• Achieved self-phase-locking of the degenerate OPO over an extended bandwidth of 3.5 nm.
• Demonstrated improved overall stability under self-phase-locking.
• Delivered up to 300 mW of output power with passive power stability better than 1.5% rms over 1.8 min.
• Obtained a Gaussian TEM00 mode profile.

Conclusions:

• Broadband self-phase-locking is successfully achieved in a degenerate cw OPO by controlling cavity dispersion.
• The self-phase-locked OPO exhibits enhanced stability and a significant bandwidth.
• This work paves the way for more robust and versatile parametric light sources.