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  Imec-ePIXfab SiPhotonics Modulators technology  

Basic characteristics

Schematic cross-sec of modulator stack

The imec modulators silicon photonic IC technology (Imec SiPhotonics) offers:
  • substrate: SOI with 220nm Si, 2000nm BOX
  • WG module(WaveGuides): 220nm full Si etch for strip waveguides, photonic crystals, ...
  • FC module (FiberCoupler): 70nm partial Si etch for fiber couplers, rib waveguides,
  • Implant Module(n1, p1, nplus, pplus, silicidation)
  • Tungsten Contact (landing on silicide)
  • M1 (Cu) for interconnect routing
  • AlCu bond pads


  • Phase modulators based on the free carrier concentration effects can be made by using P-N or P-I-N junctions.
  • Both carrier injection (forward bias) phase shifters in P-I-N or carrier depletion (reverse bias) phase shifters in P-N can be made.
  • The phase modulator section in a Mach-Zehnder interferometer or a ring resonator can be used to obtain an intensity modulator.


  • Strip waveguide (w=450nm, h=220nm) loss is 1.8-2.5 dB/cm
  • Grating Coupler (Period=630nm, duty ratio=0.50) efficiency 30%
  • Example: Modulators (lateral, interdigitated) 10Gb/s with 7-8 dB extinction ratio


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
SEM viewgraph of stack after M1 deposition


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