Skip to main content
Sandbox Physics

Optics 106 · How lasers are generated and controlled

Mode Locking & Frequency Comb

An independently initialized three-dimensional apparatus connects Random-mode phases, Locked pulse train, Comb spacing and offset. Two dimensional physical controls, direct probe dragging, a detector trace, and three quantitative checks are recalculated from the stated equation.

Interactive modelMode Locking & Frequency Comb
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 Mode Locking & Frequency Comb

BackgroundMode Locking & Frequency Comb is one independently initialized apparatus with three linked investigations: Random-mode phases, Locked pulse train, Comb spacing and offset. Its two controls—Mode count and Phase noise—feed the governing relation νn=nfrep+fCEO\nu_n=n f_{\mathrm{rep}}+f_{\mathrm{CEO}}. The validity indicator marks the paraxial, lossless, weak-field, or steady-state assumption used by this apparatus.

Why it mattersHow does locking many longitudinal phases transform continuous output into a pulse train and frequency comb?

Start with the essentials

Focus question
How does locking many longitudinal phases transform continuous output into a pulse train and frequency comb?
One-sentence intuition
The detector curve and all three numerical readouts are recomputed from νn=nfrep+fCEO\nu_n=n f_{\mathrm{rep}}+f_{\mathrm{CEO}}. 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

νn=nfrep+fCEO\nu_n=n f_{\mathrm{rep}}+f_{\mathrm{CEO}}

The implementation evaluates this relation with dimensional inputs and an executable analytic or numerical benchmark. The validity indicator marks the paraxial, lossless, weak-field, or steady-state assumption used by this apparatus.

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: Random-mode phases

    Select Random-mode phases. Sweep Mode count, hold Phase noise 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: Locked pulse train

    Select Locked pulse train. Sweep Mode count, hold Phase noise 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: Comb spacing and offset

    Select Comb spacing and offset. Sweep Mode count, hold Phase noise 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.