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  LETI-ePIXfab SiPhotonics: Passives with Heaters



LETI gives affordable access to its new photonic SOI 310nm platform on 200mm wafers. The process is based on the previous SOI220nm platform. It offers best performance for grating couplers. The multilevel option for Silicon patterning allows the design of various passive components, still coupled with thermal tuning capability by metal heaters. One AlCu level is also available for routing that is compatible with packaging.

Two process design kits (PDKs) are available through Phoenix BV suite and Cadence EDA software to help you to design your circuits, such as optical transceivers, optical switching, and many types of sensing. The PDKs give access to simulation environments such as ELDO or Aspic, and therefore allow co-simulation of complex circuits.

Basic characteristics

As shown in Figure 1, the LETI-ePIXfab SiPhotonics Passives with Heater technology consists of:

  • Substrate: SOI with 300nm Si, 800nm buried oxide
  • CD min 120nm
  • 300nm/150nm Silicon
  • 150nm/0nm Silicon
  • Optional 65nm Silicon slab thickness
  • TiN Heater layer
  • Tungsten plugs
  • 1 Metal level for routing
  • Passivation
  • Packaging-friendly (cf. Tyndall DRM)

Users can also access "passives-only" technology on the runs of "passives with heater" technology.

Figure 1a: Schematic cross section of the LETI SiPhotonics Passives with Heaters technology.
Figure 1b: Details of a rib waveguide (150nm slab; left), and a deep rib waveguide (65nm slab option; right).

Indicative performance

  Device Specification
  Coupler 1D Insertion loss < 2.5dB
  Coupler 2D Insertion loss <4.5dB
  Monomode Rib waveguide (W400nm) Loss <2.5dB/cm
  Multimode Rib waveguide Loss <0.3dB/cm
  Heater Thermal efficiency 0.2nm/mW <TE <0.5nm/mW


SiPhotonics designers target a wide range of applications:

  • Datacom and short-reach optical interconnect
  • Telecom and access networks
  • Sensors (gas, pressure, strain) and read-out ICs
  • Biomedical: biomolecule detection, drug development, point-of-care diagnostics





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