Technologies >SiPhotonics > Technology

  imec-ePIXfab SiPhotonics: passives technology


Basic characteristics

As shown in Figure 1, the imec-ePIXfab SiPhotonics passives technology consists of:

  • Substrate: SOI with 220nm Si, 2um buried oxide
  • WG module (WaveGuide): 220nm full Si etch for strip waveguides, photonic crystals, etc.
  • FC module (FiberCoupler): 70nm partial Si etch for fiber couplers, rib waveguides, etc.
  • SK module (Socket): 150nm partial Si etch
  • Cladding of choice: deposited oxide or protective resist

Figure 1: Schematic Cross section of the SiPhotonics Passive technology


The prototypes are produced in imec's 200mm wafer fab, using:

  • 0.13um mask technology (WG, FC, SK)
  • 193nm DUV lithography, optimized for generic photonics applications
  • ICP-RIE dry etch, optimized for generic photonics applications
  • Oxide deposition and CMP tools
  • Statistical process control of all tools/chambers

Indicative performance

Minimum width of lines and spacings is 150nm. Device performance as shown in the table.

  Device Specification
  Strip waveguide Loss < 3dB/cm
  Rib waveguide Loss <0.5dB/cm
  Fiber coupler (vertical) Insertion loss <6dB
  50:50 splitter Insertion loss <0.5dB


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


  High-index contrast silicon strip waveguide, 450nm (W) x 220nm (H)   Ring resonator (racetrack form). Due to the high index contrast a 5um bend radius can be used.  
  Arrayed waveguide grating (AWG) with 8 channels, 200GHz channel spacing. Device is 200um x 150um   A combination of two etch depths (FC and WG modules) is used to locally lower the refractive index contrast.  
  A grating coupler (FC module) coupling light from a single mode fiber to a strip waveguide.      


All rights reserved