Electro-optic modulation and second-harmonic generation through grating-induced resonant excitation of guided modes

Abstract

Using nonlinear polymer waveguides in integrated optics requires an adaptation of the device to the very special waveguiding characteristics of polymer films. We present in this paper new devices based on diffraction gratings for electro-optic modulation and potentially high efficient second-harmonic generation that are in general well suited to the use of polymers. We optimized the devices through numerical simulation to the use of PNA-PMMA films. We obtain experimentally 40% light modulation at L\V=5 1 .9V (r33=4.3pm/V) concerning electro-optic modulation and a conversion efficiency of =5.83* 106 iiw (X33=8pmJV) for second-harmonic generation.The performance of a nonlinear (NL) device is mainly determined by the value of the NL polarization which is the product of the NL susceptibility times the electric field present in the NL medium. High electric fields and important interaction lengths can be achieved using guided waves due to the confinement of the electromagnetic fields in the centimeter range. Guided modes, or electromagnetic resonances are widely used in non linear integrated devices like electro-optic modulators based on LiNbO3 which are already available on the market. Concerning polymer based devices, it is still difficult to cross over the step from development to manufacturing, in spite of the high non resonant values of the second order susceptibility ((2)>1OOpmJv) [1] that are already available with polymer materials. Most of the integrated devices based on polymer materials use the same basic concepts like integrated Mach Zehnder interferometers or quasi-phase-matching schemes that have been successful using inorganic materials. The technological transfer from these inorganic devices to polymer based devices often happens without taking care about the very different behavior of polymers in device fabrication, their different temporal, chemical and photo-chemical stability and their different linear optical characteristics compared to inorganic materials. The aim of this paper is to present new device concepts which can be better adapted to the specific characteristics of electric field oriented polymer materials than in the most cases of the "traditional" concepts. An example concerning electro-optic modulation and an example concerning second-harmonic generation (SHG) using artificial periodic structures will be given. The NL polymer used for the experimental demonstration of both devices is a thin film of poly(methyl methacrylate)/para-nitroaniline side-chain polymer (PNAJPMMA). O-8194-2240-1/96/$6.OO SPIE Vol. 2852 / 237 Downloaded From: http://proceedings.spiedigitallibrary.org/ on 06/29/2016 Terms of Use: http://spiedigitallibrary.org/ss/TermsOfUse.aspx

High-flux photon-pair source from electrically induced parametric down conversion after second-harmonic generation in single optical superlattice

“…In fact, some efficient SHG [18][19][20], sum-frequency generation (SFG) [21], and optical parametric oscillation (OPO) [22,23], notably thirdharmonic generation [24][25][26] in these materials have been reported. Recently, cascaded frequency conversion and signal tuning in these materials received much interest [27][28][29][30][31][32][33][34]. A quasi-phase matched (QPM) crystal composed of an unpoled lithium niobate (LN) dispersion section sandwiched between two periodically poled LN (PPLN) sections was constructed, in which amplitude modulation and frequency conversion can be obtained simultaneously by using the EO effect to control the relative phase among mixing waves [30].…”

Optical Triode Based on Electrically Induced Quadratic Cascading in an Optical Superlattice

“…In fact, some efficient SHG [12][13][14], sum-frequency generation (SFG) [15], and optical parametric oscillation (OPO) [16,17], third-harmonic generation [18][19][20] in these materials have been reported. Recently, cascaded frequency conversion and signal tuning in these materials received much interest [21][22][23][24][25][26][27][28]. A quasi-phase matched (QPM) crystal composed of an unpoled lithium niobate (LN) sandwiched between two periodically poled LN (PPLN) sections, controlled (on phase) by an external electric field, showed simultaneous amplitude modulation and frequency conversion [24].…”