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Sandbox Physics

Optics 084 · Waveguides, structured light, and modern optics

Fiber Pulse Propagation

An independently initialized three-dimensional apparatus connects Material dispersion, Chirped-pulse compensation, Zero-dispersion crossing. Two dimensional physical controls, direct probe dragging, a detector trace, and three quantitative checks are recalculated from the stated equation.

Interactive modelFiber Pulse Propagation
Primary prediction P1\mathcal P_10.500.50
Physical scale P2\mathcal P_250%50\%
Limit check V\mathcal V0.00π0.00\pi
Model regimevalid model regime\text{valid model regime}

Physics tutorial

How to investigate Fiber Pulse Propagation

BackgroundFiber Pulse Propagation is one independently initialized apparatus with three linked investigations: Material dispersion, Chirped-pulse compensation, Zero-dispersion crossing. Its two controls—Fiber length and Input chirp—feed the governing relation Δt(z)=Δt01+(β2zΔt02)2\Delta t(z)=\Delta t_0\sqrt{1+\left(\frac{\beta_2 z}{\Delta t_0^2}\right)^2}. The page uses the stated modal, coupled-mode, effective-medium, or envelope approximation and marks its breakdown instead of presenting it as a full-wave result.

Why it mattersHow do dispersion and chirp broaden, compress, or reshape an ultrashort pulse in fiber?

Start with the essentials

Focus question
How do dispersion and chirp broaden, compress, or reshape an ultrashort pulse in fiber?
One-sentence intuition
The detector curve and all three numerical readouts are recomputed from Δt(z)=Δt01+(β2zΔt02)2\Delta t(z)=\Delta t_0\sqrt{1+\left(\frac{\beta_2 z}{\Delta t_0^2}\right)^2}. Geometry and glow are presentation encodings; the equation, units, conservation or limit check, and validity indicator are the quantitative evidence.

Core mathematical model

Governing relation

Δt(z)=Δt01+(β2zΔt02)2\Delta t(z)=\Delta t_0\sqrt{1+\left(\frac{\beta_2 z}{\Delta t_0^2}\right)^2}

The implementation evaluates this relation with dimensional inputs and an executable analytic or numerical benchmark. The page uses the stated modal, coupled-mode, effective-medium, or envelope approximation and marks its breakdown instead of presenting it as a full-wave result.

Common difficulties

Mistaking glow for measured power

Typical misconceptionA brighter cinematic trail must represent proportionally more optical power.

Better mental modelUse the detector and normalized readouts for comparison. Glow is deliberately nonlinear so weak structure stays visible.

Run the experiment

  1. 01

    Scene 1: Material dispersion

    Select Material dispersion. Sweep Fiber length, hold Input chirp fixed, and then reverse the roles. Drag the stage probe to repeat the first sweep directly.

    What to observe: Read the primary prediction, physical scale, limit check, and validity indicator together. Record where the approximation boundary changes.
  2. 02

    Scene 2: Chirped-pulse compensation

    Select Chirped-pulse compensation. Sweep Fiber length, hold Input chirp fixed, and then reverse the roles. Drag the stage probe to repeat the first sweep directly.

    What to observe: Read the primary prediction, physical scale, limit check, and validity indicator together. Record where the approximation boundary changes.
  3. 03

    Scene 3: Zero-dispersion crossing

    Select Zero-dispersion crossing. Sweep Fiber length, hold Input chirp fixed, and then reverse the roles. Drag the stage probe to repeat the first sweep directly.

    What to observe: Read the primary prediction, physical scale, limit check, and validity indicator together. Record where the approximation boundary changes.