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.
