Ultra-low threshold CW Triply Resonant OPO in the near infrared using Periodically Poled Lithium Niobate

Efficient single-pass third-harmonic generation at 520 nm for pumping doubly-resonant OPO

A ~545 mW single-frequency tunable 520 nm green laser has been demonstrated using a periodically-poled potassium titanyl phosphate (PPKTP) bulk crystal based on single-pass third-harmonic generation (THG) of a 1560 nm laser via single-pass second-harmonic generation (SHG) followed by single-pass sum-frequency generation (SFG). In single-pass SHG, two cascaded periodically-poled magnesium-oxide-doped lithium niobate (PPMgO:LN) crystals were used, and ~3.5 W 780.25 nm doubled laser output is produced, corresponding to maximum doubling efficiency of 26.8%. The system can provide a pump source (52…

Observation of triply coincident nonlinearities in periodically poled KTiOPO4

We report the simultaneous quasi-phase-matching of all three possible nonlinearities for propagation along the X axis of periodocally poled (PP) KTiOPO4 (KTP) for second-harmonic generation of 745 nm pulsed light from 1490nm subpicosecond pulses in a PPKTP crystal with a 45.65 micrometer poling period. This confirms the recent Sellmeier fits of KTP by K. Kato and E. Takaoka [Appl. Opt. 41, 5040 (2002)]. Such coincident nonlinearities are of importance for realizing compact sources of multipartite continuous-variable entanglement [Pfister et al., Phys. Rev. A 70, 020302 (2004)] and we propose a…

Mapping of periodically poled crystals via spontaneous parametric down-conversion

A new method for characterization of periodically poled crystals is developed based on spontaneous parametric down-conversion. The method is demonstrated on crystals of Y:LiNbO3, Mg:Y:LiNbO3 with non-uniform periodically poled structures, obtained directly under Czochralski growth procedure and designed for application of OPO in the mid infrared range. Infrared dispersion of refractive index, effective working periods and wavelengths of OPO were determined by special treatment of frequency-angular spectra of spontaneous parametric down-conversion in the visible range. Two-dimensional mapping v…

Triply-resonant micro-optical parametric oscillators based on Kerr nonlinearity: nonlinear loss, unequal resonance-port couplings, and coupled-cavity implementations

We develop a theoretical model of triply-resonant optical parametric oscillators (OPOs) based on degenerate four-wave mixing (FWM) that includes physics and degrees of freedom relevant to microphotonic (on-chip) device implementations, including nonlinear loss, a general resonant mode field structure, and mode-selective coupling to external ports. The coupled mode theory model addresses the effect of two-photon absorption and free-carrier absorption on parametric gain and oscillation thresholds, and ultimately on the optimum design for an OPO. The model goes beyond a typical free-space cavity …

亚微米极化薄膜铌酸锂中的同时0类和I类光学参量振荡

Simultaneous Type-0 and Type-I Optical Parametric Oscillation in Submicron Poled Thin-Film Lithium Niobate

通过偏振不敏感的亚微米周期性极化，在薄膜铌酸锂微环谐振器中实现了双光学参量振荡，利用简并后向准相位匹配，单个亚微米极化周期同时支持0类和I类参量相互作用，并通过温度控制实现偏振通道选择性激活。

Mode hopping strongly affects observability of dynamical instability in optical parametric oscillators

Theoretical investigations of dynamical behavior in optical parametric oscillators (OPO) have generally assumed that the cavity detunings of the interacting fields are controllable parameters. However, OPOs are known to experience mode hops, where the system jumps to the mode of lowest cavity detuning. We note that this phenomenon significantly limits the range of accessible detunings and thus may prevent instabilities predicted to occur above a minimum detuning from being evidenced experimentally. As a simple example among a number of instability mechanisms possibly affected by this limitatio…