Reducing photorefractive effect in periodically poled ZnO- and MgO-doped LiNbO3 wavelength converters

Abstract

The photorefractive effect in annealed proton-exchanged waveguides in periodically poled nondoped, MgO- and ZnO-doped LiNbO3 was evaluated by monitoring the quasiphase matching (QPM) wavelength shift induced by a 0.784-μm-irradiating light. The QPM wavelength shift was reduced at room temperature by a factor of 3–6 in ZnO- and MgO-doped samples compared with the nondoped samples within a 104–105-W/cm2-irradiation intensity range. The doped samples exhibited no significant wavelength shifts when the temperature was raised to slightly above room temperature (50–60 °C).

A Birefringent-Refraction Transducer for Measuring Angular Displacement Based on Heterodyne Interferometry

“…In addition, nonlinear birefringent crystals such as MgO-doped lithium niobate (MgO:LN) and potassium titanyl phosphate (KTP) are also important for the wavelength converters through nonlinear optics [12,13]. Therein, MgO:LN is a uniaxial birefringent crystal with two different refractive indices.…”

“…In addition, nonlinear birefringent crystals such as It is well known that a birefringent plate (BP) has been widely applied for fabrication of wave plates and polarization splitters [11]. In addition, nonlinear birefringent crystals such as MgO-doped lithium niobate (MgO:LN) and potassium titanyl phosphate (KTP) are also important for the wavelength converters through nonlinear optics [12,13]. Therein, MgO:LN is a uniaxial birefringent crystal with two different refractive indices.…”

Tunable second harmonic generation devices with an integrated micro-heater

“…Moreover, the PPLN devices normally need to be heated over 100 °C to eliminate the refractive index change caused by photorefractive damage. Even devices based on more damage resistant MgO-or ZnOdoped LiNbo3, are usually operated at a temperature higher than room temperature (about 60 °C) to remove any possible effects of the photorefractive damage [17].…”

“…The commonly used techniques are the DFG and cascaded second harmonic generation (SHG) and DFG. In order to eliminate the wavelength shift caused by photorefractive damage, the devices normally need to be heated over 1 00 oc or use MgO-or ZnO doped LiNb03 which are more damage resistant [17].…”

Second harmonic generation at 399 nm resonant on the ^1S_0−^1P1 transition of ytterbium using a periodically poled LiNbO_3 waveguide

“…The temperature of the metal base of the PPLN waveguide was monitored with a thermistor and controlled at < 0.01 • C with a Peltier device to meet the phase matching condition. The PPLN waveguide was manufactured by NTT Electronics Corp. A 3-inch diameter 5-mol% ZnO-doped LiNbO 3 wafer of which material is highly resistant to photorefractive damage [40] and a 3-inch diameter LiTaO 3 wafer whose refractive index is lower than that of LiNbO 3 were used for the waveguide layer and substrate, respectively. Two wafers were brought into contact with each other without using any adhesives and then annealed at 500 • C to achieve complete bonding.…”