Optimization of Al2O3:Er3+ waveguide technology for active integrated optical devices

Kerstin Worhoff, J. Bradley, F. Ay, D. Geskus, Tom Blauwendraat, Markus Pollnau

    Research output: Chapter in Book/Report/Conference proceedingConference contributionAcademicpeer-review

    1 Citation (Scopus)


    Amorphous $Al_2O_3$ is a promising host material for active integrated optical applications such as tunable rare-earth-ion-doped laser and amplifier devices. The fabrication of slab and channel waveguides has been investigated and optimized by exploiting reactive co-sputtering and ICP reactive ion etching, respectively. The Al2O3 layers are grown reliably and reproducibly on thermally oxidized Si-wafers at deposition rates of 2-4 nm/min. Optical loss of as-deposited planar waveguides as low as 0.11±0.05 dB/cm at 1.5-μm wavelength has been demonstrated. The channel waveguide fabrication is based on $BCl_{3}/HBr$ chemistry in combination with standard photoresist and lithography processes. Upon process optimization channel waveguides with up to 600-nm etch depth, smooth side walls and optical losses as low as 0.21±0.05 dB/cm have been realized. Rare-earth-ion doping has been investigated by co-sputtering from a metallic Er target during $Al_2O_3$ layer growth. At the relevant dopant levels $({~}10^{20} cm^{-3})$ lifetimes of the $^{4}$$I_{13/2}$ level as high as 7 ms have been measured. Gain measurements have been carried out over 6.4-cm propagation length in a 700-nm-thick Er-doped $Al_2O_3$ waveguide. Net optical gain has been obtained over a 35-nm-wide wavelength range (1525-1560 nm) with a maximum of 4.9 dB.
    Original languageUndefined
    Title of host publicationProceedings of SPIE
    EditorsGiancarlo C. Righini, Seppo K. Honkanen, Lorenzo Pavesi, Laurent Vivien
    Place of PublicationBellingham WA 98227-0010, U.S.A.
    PublisherSPIE - The International Society for Optical Engineering
    Number of pages8
    ISBN (Print)9780819471949
    Publication statusPublished - 1 May 2008
    EventSilicon Photonics and Photonic Integrated Circuits - Strasbourg, France
    Duration: 7 Apr 200810 Apr 2008

    Publication series

    NameProceedings of SPIE
    PublisherInternational Society for Optical Engineering
    ISSN (Print)0277-786X


    ConferenceSilicon Photonics and Photonic Integrated Circuits
    Other7-10 April 2008


    • EC Grant Agreement nr.: FP6/017501
    • IOMS-APD: Active Photonic Devices
    • EWI-14300
    • IR-62577
    • METIS-254946

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