Microphotonic silicon waveguide components

Research output: Book/ReportReport

Abstract

This thesis describes the design, simulation, fabrication and characterisation of microphotonic silicon waveguide components on silicon-on-insulator (SOI) substrates. The focus is on approximately 10 µm thick and single-moded (SM) silicon rib waveguides. In particular, simulation results are given for straight and bent Si waveguides, directional couplers (DCs), thermo-optically (TO) modulated Mach-Zehnder interferometers (MZI), and waveguide gratings. A new analytical SM condition for Si rib waveguides is proposed and the development of a new grating simulation algorithm is reported. The theoretical part of the work also involves inventions relating to multi-step patterning of Si waveguides, modulation of interferometric devices, and measurement of polarisation axes from waveguides and polarisation maintaining (PM) fibers. Clean room processing of waveguide chips is briefly described. Main process steps are photolithography, electron-beam lithography, thermal oxidation, oxide deposition, oxide dry etching and Si dry etching. Post-processing of the chips is also reported, including dicing, polishing, anti-reflection (AR) coating, fiber pigtailing and wire bonding. The development of fabrication processes for multi-step patterning, waveguide gratings and photonic crystal waveguides is reported, although the optical characterisation of devices based on these three processes is not included in the thesis. Experimental results are given for Si rib waveguides with different thicknesses (H) and widths (W). The minimum fiber coupling loss with H = 9 µm was 1.3 dB/facet without an AR coating. The AR coating reduced the coupling loss by 0.7-0.8 dB/facet. Minimum propagation loss for a 114 cm long waveguide spiral with H = 9 µm and W = 7 µm was 0.13 dB/cm. With H = 9 µm, the birefringence varied from 0.00063 to <0.0001 depending on the cladding material, and the maximum polarisation extinction ratio for straight waveguides and directional couplers was >15 dB. Furthermore, fast modulation with 15 dB extinction ratio (ER) is reported for TO MZI switches by using both traditional (10 kHz) and novel (167 kHz) modulation methods. Rise and fall times for single switching operations were pushed below 750 ns with 9 dB ER. The setups and methods used in measurements are described in detail, including a novel method for measuring the polarisation axes of waveguides and PM fibers.
Original languageEnglish
Place of PublicationEspoo
PublisherVTT Technical Research Centre of Finland
ISBN (Electronic)951-38-6423-5
ISBN (Print)951-38-6422-7
Publication statusPublished - 2004
MoE publication typeD4 Published development or research report or study

Publication series

SeriesVTT Publications
Volume553
ISSN1235-0621

Fingerprint

waveguides
silicon
antireflection coatings
polarization
extinction
fibers
theses
directional couplers
gratings
Mach-Zehnder interferometers
modulation
flat surfaces
chips
etching
clean rooms
inventions
fabrication
oxides
simulation
photolithography

Keywords

  • silicon microphotonics
  • integrated optics
  • silicon-on-insulator waveguides
  • SOI waveguides
  • waveguide bends
  • thermo-optical switching
  • multi-step patterning
  • polarisation maintaining fibers
  • polarisation extinction ratio

Cite this

Aalto, T. (2004). Microphotonic silicon waveguide components. Espoo: VTT Technical Research Centre of Finland. VTT Publications, Vol.. 553
Aalto, Timo. / Microphotonic silicon waveguide components. Espoo : VTT Technical Research Centre of Finland, 2004. (VTT Publications, Vol. 553).
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Aalto, T 2004, Microphotonic silicon waveguide components. VTT Publications, vol. 553, VTT Technical Research Centre of Finland, Espoo.

Microphotonic silicon waveguide components. / Aalto, Timo.

Espoo : VTT Technical Research Centre of Finland, 2004. (VTT Publications, Vol. 553).

Research output: Book/ReportReport

TY - BOOK

T1 - Microphotonic silicon waveguide components

AU - Aalto, Timo

PY - 2004

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N2 - This thesis describes the design, simulation, fabrication and characterisation of microphotonic silicon waveguide components on silicon-on-insulator (SOI) substrates. The focus is on approximately 10 µm thick and single-moded (SM) silicon rib waveguides. In particular, simulation results are given for straight and bent Si waveguides, directional couplers (DCs), thermo-optically (TO) modulated Mach-Zehnder interferometers (MZI), and waveguide gratings. A new analytical SM condition for Si rib waveguides is proposed and the development of a new grating simulation algorithm is reported. The theoretical part of the work also involves inventions relating to multi-step patterning of Si waveguides, modulation of interferometric devices, and measurement of polarisation axes from waveguides and polarisation maintaining (PM) fibers. Clean room processing of waveguide chips is briefly described. Main process steps are photolithography, electron-beam lithography, thermal oxidation, oxide deposition, oxide dry etching and Si dry etching. Post-processing of the chips is also reported, including dicing, polishing, anti-reflection (AR) coating, fiber pigtailing and wire bonding. The development of fabrication processes for multi-step patterning, waveguide gratings and photonic crystal waveguides is reported, although the optical characterisation of devices based on these three processes is not included in the thesis. Experimental results are given for Si rib waveguides with different thicknesses (H) and widths (W). The minimum fiber coupling loss with H = 9 µm was 1.3 dB/facet without an AR coating. The AR coating reduced the coupling loss by 0.7-0.8 dB/facet. Minimum propagation loss for a 114 cm long waveguide spiral with H = 9 µm and W = 7 µm was 0.13 dB/cm. With H = 9 µm, the birefringence varied from 0.00063 to <0.0001 depending on the cladding material, and the maximum polarisation extinction ratio for straight waveguides and directional couplers was >15 dB. Furthermore, fast modulation with 15 dB extinction ratio (ER) is reported for TO MZI switches by using both traditional (10 kHz) and novel (167 kHz) modulation methods. Rise and fall times for single switching operations were pushed below 750 ns with 9 dB ER. The setups and methods used in measurements are described in detail, including a novel method for measuring the polarisation axes of waveguides and PM fibers.

AB - This thesis describes the design, simulation, fabrication and characterisation of microphotonic silicon waveguide components on silicon-on-insulator (SOI) substrates. The focus is on approximately 10 µm thick and single-moded (SM) silicon rib waveguides. In particular, simulation results are given for straight and bent Si waveguides, directional couplers (DCs), thermo-optically (TO) modulated Mach-Zehnder interferometers (MZI), and waveguide gratings. A new analytical SM condition for Si rib waveguides is proposed and the development of a new grating simulation algorithm is reported. The theoretical part of the work also involves inventions relating to multi-step patterning of Si waveguides, modulation of interferometric devices, and measurement of polarisation axes from waveguides and polarisation maintaining (PM) fibers. Clean room processing of waveguide chips is briefly described. Main process steps are photolithography, electron-beam lithography, thermal oxidation, oxide deposition, oxide dry etching and Si dry etching. Post-processing of the chips is also reported, including dicing, polishing, anti-reflection (AR) coating, fiber pigtailing and wire bonding. The development of fabrication processes for multi-step patterning, waveguide gratings and photonic crystal waveguides is reported, although the optical characterisation of devices based on these three processes is not included in the thesis. Experimental results are given for Si rib waveguides with different thicknesses (H) and widths (W). The minimum fiber coupling loss with H = 9 µm was 1.3 dB/facet without an AR coating. The AR coating reduced the coupling loss by 0.7-0.8 dB/facet. Minimum propagation loss for a 114 cm long waveguide spiral with H = 9 µm and W = 7 µm was 0.13 dB/cm. With H = 9 µm, the birefringence varied from 0.00063 to <0.0001 depending on the cladding material, and the maximum polarisation extinction ratio for straight waveguides and directional couplers was >15 dB. Furthermore, fast modulation with 15 dB extinction ratio (ER) is reported for TO MZI switches by using both traditional (10 kHz) and novel (167 kHz) modulation methods. Rise and fall times for single switching operations were pushed below 750 ns with 9 dB ER. The setups and methods used in measurements are described in detail, including a novel method for measuring the polarisation axes of waveguides and PM fibers.

KW - silicon microphotonics

KW - integrated optics

KW - silicon-on-insulator waveguides

KW - SOI waveguides

KW - waveguide bends

KW - thermo-optical switching

KW - multi-step patterning

KW - polarisation maintaining fibers

KW - polarisation extinction ratio

M3 - Report

SN - 951-38-6422-7

T3 - VTT Publications

BT - Microphotonic silicon waveguide components

PB - VTT Technical Research Centre of Finland

CY - Espoo

ER -

Aalto T. Microphotonic silicon waveguide components. Espoo: VTT Technical Research Centre of Finland, 2004. (VTT Publications, Vol. 553).