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Phase-Matching and Parametric Conversion for the Mid-Infrared in As2S3 Waveguides  [PDF]
Qi Chen, Xin Wang, Christi Madsen
Optics and Photonics Journal (OPJ) , 2012, DOI: 10.4236/opj.2012.24031

We illustrate two As2S3 waveguide designs for four-wave mixing, which can generate 3.03 μm mid-infrared light from a 1.55 μm near-infrared signal source and a 2.05 μm pump source. Through simulations, we verify that four-wave mixing phase-matching efficiencies up to 100% can be achieved using dispersion engineering to maintain the dispersion at 2.05 μm near to zero. The best conversion efficiency is –10 dB. When the waveguide length is 1 cm, the parametric conversion bandwidth is 1525 nm. We also evaluated the shift of 100% phase-matching efficiency wavelengths based upon fabrication tolerances.

Mid-infrared optical parametric amplifier using silicon nanophotonic waveguides  [PDF]
Xiaoping Liu,Richard M. Osgood Jr.,Yurii A. Vlasov,William M. J. Green
Physics , 2010, DOI: 10.1038/nphoton.2010.119
Abstract: All-optical signal processing is envisioned as an approach to dramatically decrease power consumption and speed up performance of next-generation optical telecommunications networks. Nonlinear optical effects, such as four-wave mixing (FWM) and parametric gain, have long been explored to realize all-optical functions in glass fibers. An alternative approach is to employ nanoscale engineering of silicon waveguides to enhance the optical nonlinearities by up to five orders of magnitude, enabling integrated chip-scale all-optical signal processing. Previously, strong two-photon absorption (TPA) of the telecom-band pump has been a fundamental and unavoidable obstacle, limiting parametric gain to values on the order of a few dB. Here we demonstrate a silicon nanophotonic optical parametric amplifier exhibiting gain as large as 25.4 dB, by operating the pump in the mid-IR near one-half the band-gap energy (E~0.55eV, lambda~2200nm), at which parasitic TPA-related absorption vanishes. This gain is high enough to compensate all insertion losses, resulting in 13 dB net off-chip amplification. Furthermore, dispersion engineering dramatically increases the gain bandwidth to more than 220 nm, all realized using an ultra-compact 4 mm silicon chip. Beyond its significant relevance to all-optical signal processing, the broadband parametric gain also facilitates the simultaneous generation of multiple on-chip mid-IR sources through cascaded FWM, covering a 500 nm spectral range. Together, these results provide a foundation for the construction of silicon-based room-temperature mid-IR light sources including tunable chip-scale parametric oscillators, optical frequency combs, and supercontinuum generators.
Parametric down-conversion in photonic crystal waveguides  [PDF]
Gregor Weihs
Physics , 2005, DOI: 10.1142/S0217979206034121
Abstract: Photonic crystals create dramatic new possibilities for nonlinear optics. Line defects are shown to support modes suitable for the production of pairs of photons by the material's second order nonlinearity even if the phase-matching conditions cannot be satisfied in the bulk. These structures offer the flexibility to achieve specific dispersion characteristics and potentially very high brightness. In this work, two phase matching schemes are identified and analyzed regarding their dispersive properties.
Electrical Signal-to-Noise Ratio Enhancement in Detection of Mid-IR Signals by Four-Wave Mixing in As2S3-on-LiNbO3 Waveguides  [PDF]
Qi Chen, Christi Madsen
Optics and Photonics Journal (OPJ) , 2016, DOI: 10.4236/opj.2016.65010
Abstract: Mid-infrared (mid-IR) signals can be converted to near-infrared (near-IR) wavelengths in As2S3-on-LiNbO3 waveguides by high efficiency four-wave mixing. It provided us a solution to detect mid-IR signals indirectly by state-of-the-art near-IR detectors. High efficiency four-wave mixing was demonstrated and electrical signal-to-noise ratio (eSNR) improvement was also investigated. Compared to direct detection by PbSe and HgCdTe (MCT) mid-IR detectors, the calculation indicated that, at room temperature, the indirect detection to mid-IR signals increased the electrical signal-to-noise ratio up to 67 dB.
Transmission measurement at 10.6 microns of Te2As3Se5 rib-waveguides on As2S3 substrate  [PDF]
C. Vigreux-Bercovici,E. Bonhomme,A. Pradel,J. -E. Broquin,L. Labadie,P. Kern
Physics , 2007, DOI: 10.1063/1.2430404
Abstract: The feasibility of chalcogenide rib waveguides working at lambda = 10.6 microns has been demonstrated. The waveguides comprised a several microns thick Te2As3Se5 film deposited by thermal evaporation on a polished As2S3 glass substrate and further etched by physical etching in Ar or CF4/O2 atmosphere. Output images at 10.6 microns and some propagation losses roughly estimated at 10dB/cm proved that the obtained structures behaved as channel waveguides with a good lateral confinement of the light. The work opens the doors to the realisation of components able to work in the mid and thermal infrared up to 20 microns and even more.
Spontaneous Parametric Down-Conversion and Quantum Walks in Arrays of Quadratic Nonlinear Waveguides  [PDF]
Alexander S. Solntsev,Andrey A. Sukhorukov,Dragomir N. Neshev,Yuri S. Kivshar
Physics , 2011, DOI: 10.1103/PhysRevLett.108.023601
Abstract: We analyze the process of simultaneous photon pair generation and quantum walks realized by spontaneous parametric down conversion of a pump beam in a quadratic nonlinear waveguide array. We demonstrate that this flexible platform allows for creating quantum states with different spatial correlations. In particular, we predict that the output photon correlations can be switched from photon bunching to antibunching controlled entirely classically by varying the temperature of the array or the spatial profile of the pump beam.
Correlated Photon Pair Production by Spontaneous Parametric Down Conversion in Quasi-Phase-Matched AlGaAs superlattice Waveguides using a Continuous Wave Pump  [PDF]
Peyman Sarrafi,Eric Zhu,Ksenia Dolgaleva,Barry M. Holmes,David C. Hutchings,Stewart Aitchison,Li Qian
Physics , 2013,
Abstract: We report on the demonstration of correlated photon pair generation in quasi-phase-matched superlattice AlGaAs waveguides with a high coincidence-to-accidental ratio (CAR); with a continuous (CW) pump, the observed CAR (>100) is more than two order of magnitudes improvement over previously reported spontaneous down conversion (SPDC) schemes in AlGaAs waveguides with a pulsed pump.
Spatial modes in waveguided parametric down-conversion  [PDF]
Andreas Christ,Kaisa Laiho,Andreas Eckstein,Thomas Lauckner,Peter J. Mosley,Christine Silberhorn
Physics , 2009, DOI: 10.1103/PhysRevA.80.033829
Abstract: The propagation of several spatial modes has a significant impact on the structure of the emission from parametric down-conversion in a nonlinear waveguide. This manifests itself not only in the spatial correlations of the photon pairs but also, due to new phase-matching conditions, in the output spectrum, radically altering the degree of entanglement within each pair. Here we investigate both theoretically and experimentally the results of higher-order spatial-mode propagation in nonlinear waveguides. We derive conditions for the creation of pairs in these modes and present observations of higher-order mode propagation in both the spatial and spectral domains. Furthermore, we observe correlations between the different degrees of freedom and finally we discuss strategies for mitigating any detrimental effects and optimizing pair production in the fundamental mode.
Parametric up conversion of the vacuum  [PDF]
Trevor W. Marshal
Mathematics , 1998,
Abstract: The theory of parametric down conversion of the vacuum, based on a real zeropoint, or "vacuum" electromagnetic field, has been treated in earlier articles. The same theory predicts a hitherto unsuspected phenomenon - parametric up conversion of the vacuum. This article describes how the phenomenon may be demonstrated experimentally.
Mapping of periodically poled crystals via spontaneous parametric down-conversion  [PDF]
G. Kh. Kitaeva,V. V. Tishkova,I. I. Naumova,A. N. Penin,C. H. Kang,S. H. Tang
Physics , 2005, DOI: 10.1007/s00340-005-1923-1
Abstract: 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 via spontaneous parametric down-conversion is proposed for characterizing spatial distribution of bulk quasi-phase matching efficiency across the input window of a periodically poled sample.
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