Wireless Optical Transmission at 10 Gbps and Beyond

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Wireless Optical Transmission at 10 Gbps and
Beyond
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Table of Contents

• PART I CURRENT TECHNOLOGY OVERVIEW
• Bandwidth Blowout (RF vs. IR)
• Trade-offs
• Comparison with Fiber Optics
• The atmosphere Attenuation Scattering
• Equipment Fade Margins
• PART II The PHOTONIC AIR LINK
• Basic concept
• Fiber limitations are dominant
• RF plus IR
• WDM extends bandwidth
• Optical Transformers
• Our wish list for the future

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Wireless Spectrum Carrier Frequencies
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Trade-offs between RF and IR
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Wireless Infrared Principles
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Comparison of Fiber Optics FSO (Virtual Fiber)
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Atmospheric Transmission at Sea Level
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Definition of types of ray path
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Polar diagram of scattering of red light
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Visibility Losses
 The Visibility (or visual range) is defined as
that distance where the radiance of a visible
light source is reduced to 1/50 of its initial
value V(in km) ln 50/? (in km-1) In FSO,
scattering and absorption losses are represented
in dB/km(S) so S(dB/km) 17/V(km)      
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Scattering Attenuation of Optical Beams
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Neither snow nor sleet
UWIN802 installed in Riga, Latvia by Erseta in
September, 1996. Ethernet 10 Mbps, 200 m .it
works quite well and we have no problems.
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Fade Margin Calculation

• Fade Margin calculation
• Loss Factor L.F. 10 log AB/AR dB
• -AB Beam area AR Receiver area
• -AB R2?H?V where
• -?H azimuth angle
• -?V elevation angle, R distance
•    Loss Budget L.B. 10 log PB/Pt dB
• -PB Power in the beam
• -Pt Threshold power
•    Fade Margin F.M. L.F. - L.B. dB

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Today, the Photonic Air Link has a special niche
in a niche technology Tomorrow, it may become
the key commodity in a mainstream market
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Wireless Interconnection without Electronics
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Current MMF Fibers Used in FSO
Note Gradium lens 50 mm diam. has focal length
80 mm (NA 0.3)
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Key Components of High Bandwidth Transmission
System
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Media Converter Designs
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Media Converter Designs
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RFIR 100 System
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MUX/DeMUX with MMF
1549 nm
1557 nm
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Optical Wireless WDM Experimental Arrangement
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Experimental test under FSO conditions of
Nanonics OPT XF
MMF
PAL RCVR.
SOURCE (Note 1)
Plano-convex collimator
f 80 mm
FC/PC
22 µW
MMF
1.5 meters
NANONICS DEVICE
OPT XF
Nanonics Taper (62.5 to 9 microns)
POWER METER
SMF 9 µ
17 dB loss
400 nW
Experimental test under FSO conditions of
Nanonics OPT XF
Note Same experiment repeated with taper from
200 to 70 microns and 75 micron photodiode 10
microns distant, 1 dB loss.
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Future Research

• Large core broadband fiber with high N.A.
  (BW200 MHz-km for d150 microns)
• CWDM demux with large core common input fiber
• Large core EDFA
• Low capacitance, large area photodiodes (MSM?)
  (BW 10 GHz, d80 microns)
• Migration to 10 micron wavelength