1 / 22

Free Space Laser Communications

farren
Télécharger la présentation

Free Space Laser Communications

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

    1. Free Space Laser Communications Phillip Dykstra WareOnEarth Communications Inc. phil@sd.wareonearth.com

    2. Introduction Free space laser communications a.k.a. Free Space Optics, Optical Wireless Basically a laser and a telescope Most are protocol independent Typical range < 4 km (.5, 1, 2, 4, 8km) Typical bandwidths: 10, 100, 1000 Mbps Lucent 10 Gbps DWDM (TeraBeam)

    3. Example Systems

    4. Transmitters LED (single or multiple) 1 mW typical Laser (single or multiple) 10-20 mW typical, up to 100 mW Usually 785 or 850 nm, some 1310 nm Eye safety limit: 1.5 mW/cm^2 at 785 nm Multiple transmitters boost power, may also reduce scintillation fades

    5. Detectors PIN Diodes -43 dBm typical Avalanche Photo Diodes (APD) -53 dBm typical (also greater dynamic range) Single or multiple detectors Larger aperture increases receive power, reduces scintillation fades Design goal: BER < 10^-9 typical

    6. Laser Link Geometry Critical Design Parameters

    7. System Comparison (OC3 1km products)

    8. Example Loss Budget Optical Access T1000X

    18. Fog Event (19 June 01)

    19. Fog Event (cont)

    20. Packet Loss

    21. Availability Availability = Prob (Visibility > Vmin)

    22. For More Info

More Related