FemSIM is a generalized mode solver based on the Finite Element Method (FEM) that can calculate any number of transverse or cavity modes of an arbitrary structure on a non-uniform mesh. FemSIM employs a full-vector implementation and has been enhanced with many features to compute complex modes. The tool is flexible and extendable to a wide range of problems such as high index contract, plasmonic, and photonic bandgap based waveguides.

Simulation mesh for aircore photonic crystal fiber.

Benefits

• Advanced implementation of the FEM algorithm allows for a wide range of simulation and analysis capabilities for different types of devices.
  
• Can be used in conjunction with other RSoft tools to solve for modes and then propagate them through a device.
  
• Fully integrated into the RSoft CAD Environment. (View RSoft CAD Environment link for more information).
  

Applications

FemSIM has applications for mode solving to a wide range of integrated and nano-optic devices including, but not limited to:

• Structures with arbitrary profiles, including those with curved or uncommon shapes
  
• Structures with high index contrast and/or small feature sizes
  
• Air or solid core photonic fibers
  
• Lossy structures
  
• Silicon-based devices such as SOIs
  
• Polarization rotators
  
• Plasmonic waveguides
  
• Laser and PBG defect cavities
  
  

FEATURES

• Full-vector analysis for both Cartesian and cylindrical (azimuthally symmetric) structures.
  
• Accommodates complex index for lossy materials and high index contrast profiles.
  
• Robust meshing scheme which conforms to the index profile using hybrid triangular and rectangular mesh elements.
  
• First and second order elements used to avoid spurious modes.
  
• PML and symmetric/anti-symmetric boundary conditions.
  
• Determination of propagating, leaky, and cavity modes.
  
• Higher order modes can be found with minimal additional computational expense.
  
• Computation of dispersion diagrams.
  
• Output information includes field profiles, propagation constants, overlap integrals, confinement factors, and diagnostics.
  
• Automated parametric studies and design optimization using MOST.
  
  

Simulation mesh for a rib waveguide with a tilted facet with a highly hybrid polarization both Ex and Ey components of the mode are shown.