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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

Time-space propagation maps from a generalised nonlinear Schrödinger equation model.(a–d) A GNLSE model of the pulse dynamics confirms the fission originates from free-carrier dispersion. The dashed lines indicate positions we measured along the waveguide. Note here we show the temporal power P(t) in a dB-scale relative to 1 W, whereas in Figs 1c and 2 we presented the cross-correlation of the electric field E(t), which is the quantity that we measure in the experiment. a,b correspond to the experimental conditions with low (a) and high (b) power, respectively. (c) The case modelled with solitons and a TOD perturbation. (d) Shows the case modelled with solitons, 3PA and a FCD perturbation.
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f3: Time-space propagation maps from a generalised nonlinear Schrödinger equation model.(a–d) A GNLSE model of the pulse dynamics confirms the fission originates from free-carrier dispersion. The dashed lines indicate positions we measured along the waveguide. Note here we show the temporal power P(t) in a dB-scale relative to 1 W, whereas in Figs 1c and 2 we presented the cross-correlation of the electric field E(t), which is the quantity that we measure in the experiment. a,b correspond to the experimental conditions with low (a) and high (b) power, respectively. (c) The case modelled with solitons and a TOD perturbation. (d) Shows the case modelled with solitons, 3PA and a FCD perturbation.

Mentions: Figure 3 summarizes our GNLSE modelling and confirmation that the fission event is triggered by FCD. In particular, we show the modelled pulse temporal P(t) profile along the waveguide. As a baseline, Fig. 3a,b show the GNLSE model in the linear (P0=0.5 W) and nonlinear (P0=5.9 W) regimes, respectively, with identical conditions to Fig. 2. The highest power level results in LNL=(γPo)−1=90 μm. The dashed white lines correspond to the two experimental spatial locations. We observe the pulses already split after ∼160 μm. We attribute the short fission length to a slow-light enhancement in the photonic crystal waveguide18. We now discern the roles of the different effects by switching them on and off independently in the model.


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)

Time-space propagation maps from a generalised nonlinear Schrödinger equation model.(a–d) A GNLSE model of the pulse dynamics confirms the fission originates from free-carrier dispersion. The dashed lines indicate positions we measured along the waveguide. Note here we show the temporal power P(t) in a dB-scale relative to 1 W, whereas in Figs 1c and 2 we presented the cross-correlation of the electric field E(t), which is the quantity that we measure in the experiment. a,b correspond to the experimental conditions with low (a) and high (b) power, respectively. (c) The case modelled with solitons and a TOD perturbation. (d) Shows the case modelled with solitons, 3PA and a FCD perturbation.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f3: Time-space propagation maps from a generalised nonlinear Schrödinger equation model.(a–d) A GNLSE model of the pulse dynamics confirms the fission originates from free-carrier dispersion. The dashed lines indicate positions we measured along the waveguide. Note here we show the temporal power P(t) in a dB-scale relative to 1 W, whereas in Figs 1c and 2 we presented the cross-correlation of the electric field E(t), which is the quantity that we measure in the experiment. a,b correspond to the experimental conditions with low (a) and high (b) power, respectively. (c) The case modelled with solitons and a TOD perturbation. (d) Shows the case modelled with solitons, 3PA and a FCD perturbation.
Mentions: Figure 3 summarizes our GNLSE modelling and confirmation that the fission event is triggered by FCD. In particular, we show the modelled pulse temporal P(t) profile along the waveguide. As a baseline, Fig. 3a,b show the GNLSE model in the linear (P0=0.5 W) and nonlinear (P0=5.9 W) regimes, respectively, with identical conditions to Fig. 2. The highest power level results in LNL=(γPo)−1=90 μm. The dashed white lines correspond to the two experimental spatial locations. We observe the pulses already split after ∼160 μm. We attribute the short fission length to a slow-light enhancement in the photonic crystal waveguide18. We now discern the roles of the different effects by switching them on and off independently in the model.

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