A broadband silicon electro-absorption modulator (EAM) using a Schottky diode

Uiseok Jeong, Dongchul Han, Dong Ho Lee, Kyungwoon Lee, J. Kim, Jung Ho Park

Research output: Chapter in Book/Report/Conference proceedingConference contribution

4 Citations (Scopus)


A silicon optical modulator operating at high speed and low voltage is proposed by using a Schottky diode. The optical modulation is achieved by the intensity change of guiding light due to free-carrier absorption, not conventional interference effects. The rib waveguide structure of the modulator has a height of 340 nm, a etch depth of 150 nm, a width of 4.8 μm, and a modulation length of 500 μm. It was designed to maximize the free carrier injection by a Schottky contact on the rib waveguide center. The center of the rib waveguide is lightly doped with phosphorus of 1016 cm -3, and the sides are heavily doped with phosphorus of 10 20 cm-3 to improve modulation depth by injecting free carriers into the center of the rib waveguide. This design allowed a high overlap between the optical mode and carrier density variations in the center of the waveguide. To achieve high speed operation, travelling-wave type electrodes were designed to allow co-propagation of electrical and optical signals along the waveguide. The device simulated results demonstrate a 3.3 dB modulation depth for a 500 μm modulation length with 3 Vpp driving voltages. We demonstrated a Schottky modulator operating Si EAM at 3 Vpp with a 3 dB bandwidth of 7 GHz.

Original languageEnglish
Title of host publicationIntegrated Optics
Subtitle of host publicationDevices, Materials, and Technologies XVIII
ISBN (Print)9780819499011
Publication statusPublished - 2014
EventIntegrated Optics: Devices, Materials, and Technologies XVIII - San Francisco, CA, United States
Duration: 2014 Feb 32014 Feb 5

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


OtherIntegrated Optics: Devices, Materials, and Technologies XVIII
Country/TerritoryUnited States
CitySan Francisco, CA


  • Electro-Absorption
  • Electro-optic effect
  • Rib waveguide
  • Schottky diode
  • Silicon modulator

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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