Article

# Efficiency pedestal in quasi-phase-matching devices with random duty-cycle errors

E L Ginzton Laboratory, Stanford University, Stanford, California 94305, USA.
(Impact Factor: 3.29). 03/2011; 36(6):864-6. DOI: 10.1364/OL.36.000864
Source: PubMed

ABSTRACT

It is shown that random duty-cycle errors in quasi-phase-matching (QPM) nonlinear optical devices enhance the efficiency of processes far from the QPM peak. An analytical theory is shown to agree well with numerical solutions of second-harmonic generation (SHG) in disordered QPM gratings. The measured efficiency of 1550 nm band SHG in a periodically poled lithium niobate (PPLN) waveguide away from the QPM peak agrees with observations of domain disorder in a PPLN wafer by Zygo interferometry. If suppression of parasitic nonlinear interactions is important in a specific application of QPM devices, control of random duty-cycle errors is critical.

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• "Here we fit with a quadratic function of the form α P 2 p + β P p + DC where α/β are free parameters and DC is the dark count of the detector. This is the expected behaviour of this system, the noise being a result of two processes: (i) the pump inducing photons at the input frequency via weakly phasematched down-conversion due to non-perfect poling [56] "
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• "(b) Fourier spectrum of the nonlinear distribution shown in (a). in unpoled regions. While the SH output profile in space becomes strongly dependent on the wavelength (in the absence of effective self-focusing via cascading [37] [38] [39] [40]), the randomized quasiphase matching (rQPM) process is quite broadband [41] [42] [43] [44]. "
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ABSTRACT: Export Date: 18 September 2012, Source: Scopus, Art. No.: 606892, doi: 10.1155/2012/606892, Language of Original Document: English, Correspondence Address: Assanto, G.; Nonlinear Optics and OptoElectronics Laboratory (NooEL), University Roma Tre, Via della Vasca Navale 84, 00146 Rome, Italy; email: assanto@uniroma3.it, References: De Salvo, R., Hagan, D.J., Sheik-Bahae, M., Stegeman, G., Van Stryland, E.W., Vanherzeele, H., Self-focusing and self-defocusing by cascaded secondorder effects in KTP (1992) Optics Letters, 17, pp. 28-30;
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