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Free-carrier-induced soliton fission unveiled by in situ measurements in nanophotonic waveguides.

Husko C, Wulf M, Lefrancois S, Combrié S, Lehoucq G, De Rossi A, Eggleton BJ, Kuipers L - Nat Commun (2016)

Bottom Line: We develop an analytic formalism describing the free-carrier dispersion (FCD) perturbation and show the experiment exceeds the minimum threshold by an order of magnitude.We confirm these observations with a numerical nonlinear Schrödinger equation model.These results provide a fundamental explanation and physical scaling of optical pulse evolution in free-carrier media and could enable improved supercontinuum sources in gas based and integrated semiconductor waveguides.

View Article: PubMed Central - PubMed

Affiliation: Centre for Ultrahigh bandwidth Devices for Optical Systems (CUDOS), Institute of Photonics and Optical Science (IPOS), School of Physics, University of Sydney, Sydney, New South Wales 2006, Australia.

ABSTRACT
Solitons are localized waves formed by a balance of focusing and defocusing effects. These nonlinear waves exist in diverse forms of matter yet exhibit similar properties including stability, periodic recurrence and particle-like trajectories. One important property is soliton fission, a process by which an energetic higher-order soliton breaks apart due to dispersive or nonlinear perturbations. Here we demonstrate through both experiment and theory that nonlinear photocarrier generation can induce soliton fission. Using near-field measurements, we directly observe the nonlinear spatial and temporal evolution of optical pulses in situ in a nanophotonic semiconductor waveguide. We develop an analytic formalism describing the free-carrier dispersion (FCD) perturbation and show the experiment exceeds the minimum threshold by an order of magnitude. We confirm these observations with a numerical nonlinear Schrödinger equation model. These results provide a fundamental explanation and physical scaling of optical pulse evolution in free-carrier media and could enable improved supercontinuum sources in gas based and integrated semiconductor waveguides.

No MeSH data available.


Related in: MedlinePlus

Analysis of the free-carrier perturbation generated from three-photon absorption.(a) Plot of the  perturbation and the soliton number N versus power indicating the different scalings for each ( and ). (b) GNLSE simulation showing the case with the minimum free-carrier dispersion perturbation  required for fission of a N=2 soliton. Note here we show the temporal power P(t) in a dB-scale relative to 1 W.
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f4: Analysis of the free-carrier perturbation generated from three-photon absorption.(a) Plot of the perturbation and the soliton number N versus power indicating the different scalings for each ( and ). (b) GNLSE simulation showing the case with the minimum free-carrier dispersion perturbation required for fission of a N=2 soliton. Note here we show the temporal power P(t) in a dB-scale relative to 1 W.

Mentions: In terms of characteristic physical scaling, we see that , with the material contributing via constants. The power dependence comes from the nonlinear 3PA carrier generation, whereas the To term arises due to the fact that free carriers accumulate over the pulse duration, as represented by the integral in Equation (1). It is worth highlighting that the exact scaling of κFC depends on the specific nonlinear mechanism generating the free carriers (for example, two-photon absorption, ionized gas tunneling and so on). We describe this point further in the Discussion. Note that this carrier perturbation has a completely different form to perturbations caused by TOD, Raman and SS which scale as due to a derivative term in the GNLSE, indicating these effects scale with the local pulse shape, rather than the non-local free-carrier effects31. Figure 4a shows the calculated parameters as a function of coupled peak power for our experimental conditions. We have also included the scaling of the soliton number to show the comparative evolution of these two parameters ( and ).


Free-carrier-induced soliton fission unveiled by in situ measurements in nanophotonic waveguides.

Husko C, Wulf M, Lefrancois S, Combrié S, Lehoucq G, De Rossi A, Eggleton BJ, Kuipers L - Nat Commun (2016)

Analysis of the free-carrier perturbation generated from three-photon absorption.(a) Plot of the  perturbation and the soliton number N versus power indicating the different scalings for each ( and ). (b) GNLSE simulation showing the case with the minimum free-carrier dispersion perturbation  required for fission of a N=2 soliton. Note here we show the temporal power P(t) in a dB-scale relative to 1 W.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4835551&req=5

f4: Analysis of the free-carrier perturbation generated from three-photon absorption.(a) Plot of the perturbation and the soliton number N versus power indicating the different scalings for each ( and ). (b) GNLSE simulation showing the case with the minimum free-carrier dispersion perturbation required for fission of a N=2 soliton. Note here we show the temporal power P(t) in a dB-scale relative to 1 W.
Mentions: In terms of characteristic physical scaling, we see that , with the material contributing via constants. The power dependence comes from the nonlinear 3PA carrier generation, whereas the To term arises due to the fact that free carriers accumulate over the pulse duration, as represented by the integral in Equation (1). It is worth highlighting that the exact scaling of κFC depends on the specific nonlinear mechanism generating the free carriers (for example, two-photon absorption, ionized gas tunneling and so on). We describe this point further in the Discussion. Note that this carrier perturbation has a completely different form to perturbations caused by TOD, Raman and SS which scale as due to a derivative term in the GNLSE, indicating these effects scale with the local pulse shape, rather than the non-local free-carrier effects31. Figure 4a shows the calculated parameters as a function of coupled peak power for our experimental conditions. We have also included the scaling of the soliton number to show the comparative evolution of these two parameters ( and ).

Bottom Line: We develop an analytic formalism describing the free-carrier dispersion (FCD) perturbation and show the experiment exceeds the minimum threshold by an order of magnitude.We confirm these observations with a numerical nonlinear Schrödinger equation model.These results provide a fundamental explanation and physical scaling of optical pulse evolution in free-carrier media and could enable improved supercontinuum sources in gas based and integrated semiconductor waveguides.

View Article: PubMed Central - PubMed

Affiliation: Centre for Ultrahigh bandwidth Devices for Optical Systems (CUDOS), Institute of Photonics and Optical Science (IPOS), School of Physics, University of Sydney, Sydney, New South Wales 2006, Australia.

ABSTRACT
Solitons are localized waves formed by a balance of focusing and defocusing effects. These nonlinear waves exist in diverse forms of matter yet exhibit similar properties including stability, periodic recurrence and particle-like trajectories. One important property is soliton fission, a process by which an energetic higher-order soliton breaks apart due to dispersive or nonlinear perturbations. Here we demonstrate through both experiment and theory that nonlinear photocarrier generation can induce soliton fission. Using near-field measurements, we directly observe the nonlinear spatial and temporal evolution of optical pulses in situ in a nanophotonic semiconductor waveguide. We develop an analytic formalism describing the free-carrier dispersion (FCD) perturbation and show the experiment exceeds the minimum threshold by an order of magnitude. We confirm these observations with a numerical nonlinear Schrödinger equation model. These results provide a fundamental explanation and physical scaling of optical pulse evolution in free-carrier media and could enable improved supercontinuum sources in gas based and integrated semiconductor waveguides.

No MeSH data available.


Related in: MedlinePlus