Monolithic optical parametric oscillator using chirped quasi-phase matching

Abstract

We describe a highly efficient monolithic, Q-switched, nanosecond optical parametric oscillator based on a magnesium-oxide-doped periodically poled lithium niobate crystal and containing multiple quasi-phase-matched gratings. The crystal consisted of a single unchirped grating and five gratings containing progressively increasing amounts of longitudinal chirp. The monolithic design makes the device highly compact, stable, and robust, and it demonstrated a pump-to-signal conversion efficiency of around 50%, generating 50 microJ pulses at 1.55 microm with a spectral bandwidth of 20 nm. Sonogram traces are presented showing the effect of crystal chirp on the temporal and spectral performance.

Apodization of chirped quasi-phasematching devices

“…To illustrate Eq. (18) and its accuracy, we show in Fig. 1 the propagation of the idler as a function of z for a particular linearly chirped grating.…”

“…(17) and (18) to develop a heuristic criterion by which apodization profiles can be constructed. These apodization regions will be appended to the ends of a nominal grating profile (e.g., linearly chirped); we illustrate different types of apodization in Section 4.…”

Structural investigation of LN/LT¹ superlattice thin films by field effect scanning transmission electron microscopy equipped with electron disspersive x-ray spectroscopy

“…Among several methods for fabrication of thin films, e.g., sputtering [7], liquid phase epitaxy [8], sol-gel method [9], etc, the PLD method has advantages over others in the following points, (1) materials stoichiometry can be maintained, (2) oxygen-deficiencies can be controlled by adjustment of atmospheric gas pressure and (3) film's thickness is simply proportional to the number of the pulses radiated onto the targets [10].…”

“…LiNbO 3 and LiTaO 3 are representative ferroelectrics which have been used in wide range of opto-electronic applications such as quasi phase matching (QPM) devises for green laser sources [1], optical parametric oscillator [2], optical waveguides [3], and optical modulators [4]. In recent years, it has been getting more and more important to investigate silicon-ferroelectrics combined devices ． in a. monolithic form, to make devices smaller, more efficient and cost-effective [5] in association with the rapid development of mobile communication devices.…”

Engineering of effective second-order nonlinearity in uniform and chirped gratings

“…Chirped QPM gratings have been utilized to achieve broadband conversion, e.g., in aperiodically poled lithium niobate (APPLN) in broadband second harmonic generation (SHG) [14][15][16][17][18][19]; however, the conversion efficiency response suffers from ripples. These ripples cause the output of second harmonic (SH) power to vary with wavelength, and the use of an optical equalizer for chirped periodically poled lithium niobate is thus required [19].…”