Connectivity Unlimited TM Wireless Optical Transmission at 10 Gbps and Beyond
Connectivity Unlimited TM Slide No. 2 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
Connectivity Unlimited TM Slide No. 3 Wireless Spectrum Carrier Frequencies
Connectivity Unlimited TM Slide No. 4 Trade-offs between RF and IR
Connectivity Unlimited TM Slide No. 5 Wireless Infrared Principles
Connectivity Unlimited TM Slide No. 6 Comparison of Fiber Optics & FSO (Virtual Fiber) Yyyyyyyyy yyyyyyy <50 dB
Connectivity Unlimited TM Slide No. 7 Atmospheric Transmission at Sea Level
Connectivity Unlimited TM Slide No. 8 Definition of types of ray path
Connectivity Unlimited TM Slide No. 9 Polar diagram of scattering of red light
Connectivity Unlimited TM Slide No. 10 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)
Connectivity Unlimited TM Slide No. 11 Scattering Attenuation of Optical Beams Weather Condition Attenuation (dB/km) at 850 nm Visibility (km) Clear weather, light haze 0 to 3 50 to 6 Light rain 3 to 6 6 to 3 Heavy rain 6 to 17 3 to 1 Snow 10 to to 0.5 Light fog 17 to 70 1 to 0.25 Heavy fog 80 to to 0.08 Clouds 300 to to 0.03
Connectivity Unlimited TM Slide No. 12 Neither snow nor sleet… UWIN802 installed in Riga, Latvia by “Erseta” in September, Ethernet 10 Mbps, ~200 m “….it works quite well and we have no problems”.
Connectivity Unlimited TM Slide No. 13 ARAR ABAB HH ABAB ARAR Fade Margin Calculation Fade Margin calculation Loss Factor = L.F. = 10 log A B /A R [dB] -A B = Beam area; A R = Receiver area -A B ~ R 2 H V where - H = azimuth angle - V = elevation angle, R = distance Loss Budget = L.B. = 10 log P B /P t [dB] -P B = Power in the beam -P t = Threshold power Fade Margin = F.M. = L.F. - L.B. [dB] R
Connectivity Unlimited TM Slide No. 14 Today, the Photonic Air Link has a special niche in a niche technology Tomorrow, it may become the key commodity in a mainstream market
Connectivity Unlimited TM Slide No. 15 Wireless Interconnection without Electronics
Connectivity Unlimited TM Slide No. 16 Current MMF Fibers Used in FSO Fiber type Core diam. (microns) NABandwidthMHz.km Max length at Gigabit ETH (meters) Graded Index Semi GI Step Index Note: Gradium lens 50 mm diam. has focal length 80 mm (NA ≈ 0.3)
Connectivity Unlimited TM Slide No. 17 Key Components of High Bandwidth Transmission System Network switch, PABX, etc Network Interface Unit (in or near the equipment closet) TX RX f.o cable NIU Duplex f.o. cable connectors Up to 50 m Optical Antenna Module (OAM) (on Roof or Tower) TX RX
Connectivity Unlimited TM Slide No. 18 Media Converter Designs
Connectivity Unlimited TM Slide No. 19 Media Converter Designs
Connectivity Unlimited TM Slide No. 20 RFIR 100 System
Connectivity Unlimited TM Slide No. 21 MUX/DeMUX with MMF 1549 nm 1557 nm
Connectivity Unlimited TM Slide No. 22 Optical Wireless WDM Experimental Arrangement
Connectivity Unlimited TM Slide No. 23 Experimental test under FSO conditions of Nanonics OPT XF SOURCE (Note 1) Experimental test under FSO conditions of Nanonics OPT XF PAL RCVR. MMF Plano-convex collimator f = 80 mm 1.5 meters OPT XF FC/PC 22 μW MMF SMF 9 μ POWER METER NANONICS DEVICE 400 nW Nanonics Taper (62.5 to 9 microns) 17 dB loss Note: Same experiment repeated with taper from 200 to 70 microns and 75 micron photodiode 10 microns distant, 1 dB loss.
Connectivity Unlimited TM Slide No. 24 Future Research Large core broadband fiber with high N.A. (BW>200 MHz-km for d>150 microns) CWDM demux with large core common input fiber Large core EDFA Low capacitance, large area photodiodes (MSM?) (BW ≈10 GHz, d≥80 microns) Migration to 10 micron wavelength