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FIMMPROP

Bi-directional optical propagation tool

FIMMPROP

End-facet Coupling

Simulations with FIMMPROP software

3D bi-directional propagation tool FIMMPROP

When trying to optimise and characterise the transmission from an optical fibre to the end facet of an optical chip, a large number of parameters can be optimised.

Our 3D bi-directional propagation tool FIMMPROP allows you to model with great efficiency and accuracy the influence of various effects such as:

  • fiber-to-chip mode size matching (spot size matching),
  • fiber-to-chip mode index matching,
  • optimisation of the waveguide / fiber geometry and dimensions,
  • fiber-to-chip alignment,
  • existence and length of a free-space gap in between the fibre and the chip,
  • tapering of the waveguide (spot-size converter),
  • thin-film filters, anti-reflection coatings,
  • fiber lensing.

Note that FIMMPROP can also model other types of fiber to chip couplers, including surface-emitting gratings, and various mode size converters (or spot size converters) such as grating-assisted mode size converters and inverted tapers.

Unlike a BPM, FDTD or FEM tool, FIMMPROP is able to generate fast optimisation of such structures, thanks to its fast scanning capability which only needs to re-calculate the parts of the simulation that have changed.

In the example below we are optimising fiber-to-chip vertical alignment for a butt coupled structure with a 100nm air gap.