A micromachined variable optical attenuator (VOA)

Jingqi Li*, X. M. Zhang, A. Q. Liu, Q. X. Zhang, T. Mei

*Corresponding author for this work

    Research output: Contribution to journalConference articlepeer-review

    2 Scopus citations


    Variable optical attenuator (VOA) is undergoing to be a mainstream component of wavelength division multiplex (WDM) networks to monitor and control the optical power of wavelength channels. In this paper, a free-space VOA fabricated by micro electromechanical systems (MEMS) technology to operate in the 1.55 μm wavelength region is described. It employs a micromirror driven by an electrostatic comb drive to cut partially into the light beam between two single mode fibers (SMFs), enabling the attenuation. The micromirror has a size of 30 μm × 30 μm and is coated with aluminum to increase the reflectance. The moving fingers of comb drive and the micromirror are supported by folded suspension beams over the substrate. By applying different voltage to the comb drive, the micromirror translates to different position to achieve an attenuation ranging from 0.4dB to 50dB, and even higher. The nonlinear relationship between the position of the micromirror and attenuation is analyzed. The distributions of the light beams at the micromirror and the output fiber end are investigated respectively. And the influence of the separations between the micromirror, the input and output fiber ends is also discussed to obtain different attenuation resolutions. At low attenuation stages, fine tuning of attenuation is obtainable. The largest attenuation is driven by 21 voltage. Deep reactive ion etching (DRIE) process is employed to fabricate the VOA and the micro loading effect is remedied by mask design.

    Original languageEnglish (US)
    Pages (from-to)112-120
    Number of pages9
    JournalProceedings of SPIE - The International Society for Optical Engineering
    StatePublished - Dec 1 2001
    EventOptical Switching and Optical Interconnection - Beijing, China
    Duration: Nov 12 2001Nov 15 2001


    • DRIE
    • MEMS
    • Micromirror
    • VOA
    • WDM

    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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