On-chip positionable photonic waveguides for chip-to-chip optical interconnects

Tjitte Jelte Peters, Marcel Tichem*

*Corresponding author for this work

Research output: Chapter in Book/Conference proceedings/Edited volumeConference contributionScientificpeer-review

3 Citations (Scopus)
73 Downloads (Pure)


This paper reports on the progress related to a multichannel photonic alignment concept, aiming for sub-micrometer precision in the alignment of the waveguides of two photonic integrated circuits (PICs). The concept consists of two steps: chip-to-chip positioning and chip bonding provide a coarse alignment after which waveguide-to-waveguide positioning and fixing result in a fine alignment. For the waveguide-to-waveguide alignment, an alignment functionality is developed and integrated in one of the PICs, consisting of mechanically flexible waveguides and MEMS actuators. This paper reports on the fabrication and characterization of a mechanically flexible waveguide array that can be positioned by two out-of-plane actuators. Thermal actuators are integrated with mechanically flexible waveguide beams to enable positioning them with high precision. By adding a poly-Si pattern on top of SiO2 beams, an out-of-plane bimorph actuator can be realized. An analytical model enables estimating the curvature and the deflection of a single bimorph beam. Acquiring a small initial deflection while having a large motion range of the actuator proves to have conflicting demands on the poly-Si/SiO2 thickness ratio. In this paper, we show that suspended waveguide arrays with integrated alignment functionality have an initial deflection- they curl up- due to residual stress in the materials. The actuators can be operated using a driving voltage between 0V to 45V, corresponding to ∼50mW. Using higher voltages brings the risk of permanently changing the material properties of the heaters. The actuators can accomplish an out-of-plane crossbar translation up to 6.5 μm at ∼50mW as well as a rotation around the propagation direction of the light ranging from -0:1° to 0.1°. At a constant actuation power of ∼50mW, the crossbar shows a drift in vertical deflection of 0.16 μm over a time of 30 min.

Original languageEnglish
Title of host publicationSilicon Photonics and Photonic Integrated Circuits V
EditorsLaurent Vivien, Lorenzo Pavesi, Stefano Pelli
Place of PublicationBellingham, WA, USA
Number of pages10
ISBN (Electronic)978-1-510601369
Publication statusPublished - 2016
EventSilicon Photonics and Photonic Integrated Circuits V - Brussels, Belgium
Duration: 3 Apr 20167 Apr 2016

Publication series

NameProceedings of SPIE
ISSN (Electronic)1996-756X


ConferenceSilicon Photonics and Photonic Integrated Circuits V


  • Alignment
  • Bimorph actuator
  • Deection
  • MEMS
  • Optical interconnect
  • Photonics
  • Stability
  • Waveguides


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