| 1. |
- Cuadra, Jorge, 1982, et al.
(författare)
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Hybrid dielectric waveguide spectroscopy of individual plasmonic nanoparticles
- 2017
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Ingår i: AIP Advances. - : AIP Publishing. - 2158-3226 .- 2158-3226. ; 7:7, s. Article no: 075207 -
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Tidskriftsartikel (refereegranskat)abstract
- Plasmonics is a mature scientific discipline which is now entering the realm of practical applications. Recently, significant attention has been devoted to on-chip hybrid devices where plasmonic nanoantennas are integrated in standard Si 3 N 4 photonic waveguides. Light in these systems is usually coupled at the waveguide apexes by using multiple objectives and/or tapered optical fibers, rendering the analysis of spectroscopic signals a complicated task. Here, we show how by using a grating coupler and a low NA objective, quantitative spectroscopic information similar to standard dark-field spectroscopy can be obtained at the single-nanoparticle level. This technology may be useful for enabling single-nanoparticle studies in non-linear excitation regimes and/or in complex experimental environments, thus enriching the toolbox of nanophotonic methods.
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| 2. |
- Fülöp, Attila, 1988, et al.
(författare)
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Phase-sensitive resonant four-wave mixing in silicon nitride microresonators
- 2015
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Ingår i: European Conference on Lasers and Electro-Optics, CLEO 2015; Munich; Germany; 21 June 2015 through 25 June 2015. - 9781467374750 - 9781467374750 ; , s. CD_P_9-
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Konferensbidrag (refereegranskat)abstract
- We have investigated the phase sensitive nature of resonant four-wave mixing in silicon nitride microresonators. The generated idlers show a clear periodic behavior as a function of the input signal’s phase matching our simulations.
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| 3. |
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| 4. |
- Fülöp, Attila, 1988, et al.
(författare)
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Resonant nonlinear effects in silicon nitride microresonators
- 2014
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Ingår i: Optics & Photonics in Sweden, 11-12 Nov. 2014, Göteborg.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Silicon nitride is a fully CMOS-compatible material that in recent years has been gaining significant attention for realizing nonlinear optics at the chip scale. Its properties include low linear losses and absence of two-photon absorption. In terms of applications, parametric mixing and WDM-compatible light generation are both possible and thus make it an ideal material for microresonators.In this work we have investigated the linear and nonlinear properties of dual-layer silicon nitride resonators through both simulations and experiments. The devices are manufactured by LioniX and have the added advantage of being single-mode.The linear properties are shown in Fig. 1, the mode profile and the dispersion of the dual-layer waveguides have been simulated using COMSOL. In this poster, we will present our most recent experimental investigations that illustrate the coherent phase-sensitive nature of the resonant four-wave mixing in these devices.
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| 5. |
- Fülöp, Attila, 1988, et al.
(författare)
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Triply resonant coherent four-wave mixing in silicon nitride microresonators
- 2015
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Ingår i: Optics Letters. - 0146-9592 .- 1539-4794. ; 40:17, s. 4006-4009
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Tidskriftsartikel (refereegranskat)abstract
- The generation of multiple tones using four-wave mixing (FWM) has been exploited for many applications, ranging from wavelength conversion to frequency comb generation. FWM is a coherent process, meaning that its dynamics strongly depends on the relative phase among the waves involved. The coherent nature of FWM has been exploited for phase-sensitive processing in different waveguide structures, but it has never been studied in integrated microresonators. Waveguides arranged in a resonant way allow for an effective increase in the wavelength conversion efficiency (at the expense of a reduction in the operational bandwidth). In this letter, we show that phase shaping of a three-wave pump provides an extra degree of freedom for controlling the FWM dynamics in microresonators. We present experimental results in single-mode, normal-dispersion high-Q silicon nitride resonators, and numerical calculations of systems operating in the anomalous dispersion regime. Our results indicate that the wavelength conversion efficiency and modulation instability gain in microcavities pumped by multiple waves can be significantly modified with the aid of simple lossless coherent control techniques.
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| 6. |
- Krückel, Clemens, 1984, et al.
(författare)
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Bandgap engineering in nonlinear silicon nitride waveguides
- 2017
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Ingår i: 2017 Optical Fiber Communication Conference (OFC). - 9781943580231 ; , s. M3F.6 -
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Konferensbidrag (refereegranskat)abstract
- We show that controlling the bandgap of SiN provides an additional degree of freedom for engineering waveguides for nonlinear optics. We show an optimized structure with gamma*maxLeff = 0.17 rad/W and absence of nonlinear loss.
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| 7. |
- Krückel, Clemens, 1984, et al.
(författare)
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Continuous-wave nonlinear optics in low-stress silicon-rich nitride waveguides
- 2015
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Ingår i: Optical Fiber Communication Conference (OFC, Los Angeles, California US, March 22-26, 2015). - 9781557529374
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Konferensbidrag (refereegranskat)abstract
- We demonstrate CW-pumped wavelength conversion in low-stress silicon-rich nitridewaveguides. The ability to grow thick silicon-rich layers simultaneously enables high-field confinement,dispersion engineering and handling high-power levels without two-photon absorption effects.
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| 8. |
- Krückel, Clemens, 1984, et al.
(författare)
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Continuous wave-pumped wavelength conversion in low-loss silicon nitride waveguides
- 2015
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Ingår i: Optics Letters. - 0146-9592 .- 1539-4794. ; 40:6, s. 875-878
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Tidskriftsartikel (refereegranskat)abstract
- In this Letter we introduce a complementary metal-oxide semiconductor (CMOS)-compatible low-loss Si3N4 waveguideplatform for nonlinear integrated optics. The waveguide has a moderate nonlinear coefficient of 285 W∕km,but the achieved propagation loss of only 0.06 dB∕cm and the ability to handle high optical power facilitate anoptimal waveguide length for wavelength conversion. We observe a constant quadratic dependence of the four-wavemixing (FWM) process on the continuous-wave (CW) pump when operating in the C-band, which indicates that thewaveguide has negligible high-power constraints owing to nonlinear losses. We achieve a conversion efficiency of−26.1 dB and idler power generation of −19.6 dBm. With these characteristics, we present for the first time, to the best of our knowledge, CW-pumped data conversion in a non-resonant Si3N4 waveguide.
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| 9. |
- Krückel, Clemens, 1984
(författare)
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Integrated Nonlinear Optics in Silicon Nitride Waveguides
- 2015
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Integrated optics platforms offer the possibility to implement compact photonic devices for nonlinear optics applications. Modern nanofabrication facilities allow thefabrication of sub-micron-sized waveguide geometries that confine light to reach very high optical intensities. These intensities enable efficient nonlinear processes that are further enhanced by using materials with high nonlinear Kerr coefficients. Additionally, dispersion engineering by changing the waveguide dimensions allows for broadband operation.In this thesis, we explored silicon nitride as the core material of silica embedded waveguides. Silicon nitride does not show nonlinear loss constraints, which makes this material very suitable for high optical intensities. The material has a large transparency window, from the ultraviolet to the short-wave infrared, and it is completelycompatible with CMOS fabrication standards. The potential of this platform for diverse linear and nonlinear optics applications has been demonstrated before.We studied two slightly distinct material platforms: stoichiometric silicon nitride, Si3N4, and non-stoichiometric silicon nitride, SixNy. The accessible Si3N4 material platform consisted of thin low-confinement waveguides with low propagation loss of 0.06 dB/cm and a moderate nonlinear coefficient of 285 (W*km)^-1. Ina 1 m long waveguide the nonlinear performance was studied experimentally. The realized four-wave mixing (FWM) experiment showed a conversion efficiency of -26.1 dB and ultrafast all optical signal processing was demonstrated by wavelength conversion of high-speed data. The SixNy material was processed to realize thick high-confinement waveguides that show propagation loss of around 1 dB/cm and a nonlinear coefficient of 6100 (W*km)^-1. The material specific nonlinear Kerr coefficient was 1.4*10^18 m2/W, which is five times higher than Si3N4. With this materialplatform the fabrication of thick layers up to 700 nm in a single deposition step was demonstrated, a procedure not possible in Si3N4. The thick layers enable broadband dispersion engineering.
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| 10. |
- Krückel, Clemens, 1984
(författare)
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Integrated Nonlinear Optics in Silicon Nitride Waveguides
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Current nanofabrication techniques allow patterning of optical waveguides with submicron cores. This results in strong confinement of light, which leads to high optical intensities. If the waveguides are fabricated with materials that display a large nonlinear Kerr coefficient, then nonlinear optical phenomena can take place in a very efficient manner. Silicon nitride is a very well-studied material in the electronics industry. The material has a large transparency window, from the ultraviolet to the short-wave infrared, and its fabrication is completely compatible with standard techniques formerly developed by the semiconductor industry. Silicon nitride strip waveguides can also confine light, and diverse applications based on nonlinear optics have been demonstrated before. However, these applications required core thickness above 300 nm and they are very challenging to fabricate in a reliable manner with standard deposition techniques. In this thesis, we have studied unconventional silicon nitride waveguides that are more robust for fabrication. The first layout corresponds to a thin strip waveguide with low optical confinement and propagation losses of only 6 dB/m. This technology was originally developed at the University of California, Santa Barbara. We used the technology to demonstrate wavelength conversion of high-speed data. In this thesis, we developed another silicon nitride technology that allowed for high light confinement. We discovered that by modifying the stoichiometry of the film during the deposition process, one could drastically change the optical and mechanical properties of the material. With this technology we demonstrated octave-spanning supercontinuum generation in collaboration with the Technical University of Denmark and XPM-based all-optical processing in collaboration with McGill University. These results indicate that this platform is very suitable for nonlinear integrated optics. The long-term goal of our research is being able to attain an optical parametric amplifier on chip using a continuous-wave pump laser source. In this thesis we benchmarked the losses of high-confinement waveguides for the realization of 10 dB parametric net-gain on chip and identified silicon nitride as the most plausible technology to achieve this goal in the near future.
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| 11. |
- Krückel, Clemens, 1984, et al.
(författare)
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Linear and nonlinear characterization of low-stress high-confinement silicon-rich nitride waveguides
- 2015
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Ingår i: Optics Express. - 1094-4087 .- 1094-4087. ; 23:20, s. 25827-25837
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Tidskriftsartikel (refereegranskat)abstract
- In this paper we introduce a low-stress silicon enriched nitride platform that has potential for nonlinear and highly integrated optics. The manufacturing process of this platform is CMOS compatible and the increased silicon content allows tensile stress reduction and crack freelayer growth of 700 nm. Additional benefits of the silicon enriched nitride is a measured nonlinear Kerr coefficient n2 of 1.4*10^18 m2/W (5 times higher than stoichiometric silicon nitride) and a refractive index of 2.1 at 1550 nm that enables high optical field confinement allowing high intensity nonlinear optics and light guidance even with small bending radii. We analyze the waveguide loss (~1 dB/cm) in a spectrally resolved fashion and include scattering loss simulations based on waveguide surface roughness measurements. Detailed simulations show the possibility for fine dispersion and nonlinear engineering. In nonlinear experiments we present continuouswave wavelength conversion and demonstrate that the material does not show nonlinear absorption effects. Finally, we demonstrate microfabrication of resonators with high Q-factors (~10^5).
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| 12. |
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| 13. |
- Krückel, Clemens, 1984, et al.
(författare)
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Optical bandgap engineering in nonlinear silicon nitride waveguides
- 2017
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Ingår i: Optics Express. - 1094-4087 .- 1094-4087. ; 25:13, s. 15370-15380
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Tidskriftsartikel (refereegranskat)abstract
- Silicon nitride is a well-established material for photonic devices and integrated circuits. It displays a broad transparency window spanning from the visible to the mid-IR and waveguides can be manufactured with low losses. An absence of nonlinear multi-photon absorption in the erbium lightwave communications band has enabled various nonlinear optic applications in the past decade. Silicon nitride is a dielectric material whose optical and mechanical properties strongly depend on the deposition conditions. In particular, the optical bandgap can be modified with the gas flow ratio during low-pressure chemical vapor deposition (LPCVD). Here we show that this parameter can be controlled in a highly reproducible manner, providing an approach to synthesize the nonlinear Kerr coefficient of the material. This holistic empirical study provides relevant guidelines to optimize the properties of LPCVD silicon nitride waveguides for nonlinear optics applications that rely on the Kerr effect.
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| 14. |
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| 15. |
- Krückel, Clemens, 1984, et al.
(författare)
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Towards on-chip net-gain in CMOS-compatible waveguides
- 2017
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Ingår i: Conference on Lasers and Electro-Optics (CLEO) Europe.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- We theoretically investigate performance requirements to achieve on-chip optical parametric net-gain of 10 dB with CW pump. The investigations cover high confinement CMOS-compatible waveguides based on silicon nitride and silicon.
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| 16. |
- Krückel, Clemens, 1984, et al.
(författare)
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Wavelength Conversion in Low Loss Si3N4 Waveguides
- 2014
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Ingår i: Optics InfoBase Conference Papers. - Washington, D.C. : OSA. - 2162-2701. ; , s. SW3M.4-
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Konferensbidrag (refereegranskat)abstract
- We show wavelength conversion in a compact Si3N4 waveguide. Combining low loss, long length, relatively large nonlinear coefficient, high-power handling and absence of two-photon absorption, this platform is promising for integrated nonlinear optics applications.
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| 17. |
- Liu, Xing, et al.
(författare)
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Octave-spanning Supercontinuum Generation in a Silicon-rich Nitride Waveguide
- 2016
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Ingår i: 2016 Conference on Lasers and Electro-Optics, CLEO 2016. - 9781557528209
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Konferensbidrag (refereegranskat)abstract
- We generate supercontinuum (817 – 2250 nm at -30dB) in a dispersion-engineered silicon-rich nitride waveguide by pumping fs pulses with 82 pJ from an erbium-fiber oscillator. Spectral broadening mechanisms include soliton fission and dispersive wave generation.
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| 18. |
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| 19. |
- Rezagholipour Dizaji, Mohammad, et al.
(författare)
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Cross-Phase-Modulation-Based Wavelength Conversion in Low-Stress Silicon-Rich Nitride Waveguide
- 2016
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Ingår i: 2016 Optical Fiber Communications Conference and Exhibition (Ofc). - Washington, D.C. : OSA. - 9781943580071
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Konferensbidrag (refereegranskat)abstract
- We report cross-phase-modulation-based wavelength conversion of 10 Gb/s RZ-OOK using a low-stress silicon-rich nitride waveguide. The waveguide is engineered to display flat and low dispersion over the entire C+L bands.
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| 20. |
- Rezagholipour Dizaji, Mohammad, et al.
(författare)
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Silicon-rich nitride waveguides for ultra-broadband nonlinear signal processing
- 2017
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Ingår i: Optics Express. - 1094-4087 .- 1094-4087. ; 25:11, s. 12100-12108
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Tidskriftsartikel (refereegranskat)abstract
- Silicon nitride (SixNy) waveguides constitute a technology platform to realize optical signal processing based on the nonlinear Kerr effect. Varying the stoichiometry of the core (i. e., x and y in silicon nitride) provides an additional degree of freedom for engineering the waveguide properties, such as nonlinear Kerr parameter and dispersion. We demonstrate low-stress high-confinement silicon-rich nitride waveguides with flat and anomalous dispersion over the entire C and L optical wavelength transmission bands for optical signal processing based on cross-phase modulation. The waveguides do not show any nonlinear loss for a measured optical input intensity of up to 1.5 x 109 W/cm(2). In particular, we achieve wavelength conversion of 10 Gb/s signals across the C band; XPM broadening is also observed in the O band. In addition, we highlight the use of SixNy waveguides for nonlinear microwave photonics. Specifically, we demonstrate radio-frequency spectral monitoring of optical signals with a bandwidth of hundreds of gigahertz.
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| 21. |
- Torres Company, Victor, 1981, et al.
(författare)
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High-confinement high-Q silicon-rich silicon nitride nonlinear microresonators
- 2018
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Ingår i: Optics InfoBase Conference Papers. - 2162-2701. ; Part F101-IPRSN 2018:2018
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Konferensbidrag (refereegranskat)abstract
- We show our results on high-Q high-confinement microresonators based on the silicon-rich silicon nitride (SiRN) platform, featuring broad anomalous dispersion and an enhanced nonlinear Kerr coefficient with respect to stoichiometric Si3N4 technology.
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| 22. |
- Torres Company, Victor, 1981, et al.
(författare)
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Silicon-rich Nitride Waveguides for Broadband Nonlinear Signal Processing
- 2017
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Ingår i: Optics InfoBase Conference Papers. - 2162-2701. ; Part F122-CLEOPR 2017, s. 1-3
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Konferensbidrag (refereegranskat)abstract
- Silicon nitride waveguides are among the most promising platforms for nonlinear optical processing applications. In this invited contribution we will highlight how the dispersion and Kerr coefficient (n2) can be tuned by precisely controlling the stoichiometry of the waveguide's core material.
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| 23. |
- Xing, Liu, et al.
(författare)
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Octave-spanning supercontinuum generation in a silicon-rich nitride waveguide
- 2016
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Ingår i: Optics Letters. - 0146-9592 .- 1539-4794. ; 41:12, s. 2719-2722
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Tidskriftsartikel (refereegranskat)abstract
- We experimentally show octave-spanning supercontinuum generation in a nonstoichiometric silicon-rich nitride waveguide when pumped by femtosecond pulses from an erbium fiber laser. The pulse energy and bandwidth are comparable to results achieved in stoichiometric silicon nitride waveguides, but our material platform is simpler to manufacture. We also observe wave-breaking supercontinuum generation by using orthogonal pumping in the same waveguide. Additional analysis reveals that the waveguide height is a powerful tuning parameter for generating mid-infrared dispersive waves while keeping the pump in the telecom band.
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