Experimental comparison of performance degradation from terahertz and infrared wireless links in fog.

We describe a lab setup for analyzing impairments of terahertz (THz) and infrared (IR) free space links caused by local refraction index changes in the signal's propagation paths that could be induced by turbulence, particles, humidity, etc. A THz signal comprising a 2.5 Gb/s data load modulated on a carrier at 625 GHz, is launched through a weather emulating chamber, detected, and its performance analyzed. An IR beam at 1.5 um wavelength carrying the same data load is superposed with the THz beam, propagating through the same weather conditions and also performance analyzed. We modulate the IR channel with a usual non-return-to-zero (NRZ) format but use duobinary coding for driving our THz source, which enables signaling at high data rate and higher output power. As both beams pass through the same channel perturbations and as their degradations are recorded simultaneously we can simultaneously compare the weather impact on both. We investigate scintillation and fog attenuation effects for the THz and IR signals by measuring bit error rates (BER), signal power, and phase front distortions.

[1]  Zabih Ghassemlooy,et al.  Bit error rate measurement of free space optical communication links under laboratory-controlled fog conditions , 2011, 2011 16th European Conference on Networks and Optical Communications.

[2]  N. Kukutsu,et al.  Effect of Rain Attenuation for a 10-Gb/s 120-GHz-Band Millimeter-Wave Wireless Link , 2009, IEEE Transactions on Microwave Theory and Techniques.

[3]  Tadao Nagatsuma,et al.  A Review on Terahertz Communications Research , 2011 .

[4]  Adam Lender,et al.  The duobinary technique for high-speed data transmission , 1963, Transactions of the American Institute of Electrical Engineers, Part I: Communication and Electronics.

[5]  T. Mizuochi,et al.  Recent progress in forward error correction and its interplay with transmission impairments , 2006, IEEE Journal of Selected Topics in Quantum Electronics.

[6]  J. Federici,et al.  2.5 Gbit/s duobinary signalling with narrow bandwidth 0.625 terahertz source , 2011 .

[7]  E. Leitgeb,et al.  Experimental study of bit error rate of free space optics communications in laboratory controlled turbulence , 2010, 2010 IEEE Globecom Workshops.

[8]  M. Sekine,et al.  Rain Attenuation at 103 GHz in Millimeter Wave Ranges , 2005 .

[9]  Emilien Peytavit,et al.  Optically power supplied Gbit/s wireless hotspot using 1.55 μm THz photomixer and heterodyne detection at 200 GHz , 2010 .

[10]  L. Andrews,et al.  Laser Beam Scintillation with Applications , 2001 .

[11]  Tho Le-Ngoc,et al.  Leveraging green communications for carbon emission reductions: Techniques, testbeds, and emerging carbon footprint standards , 2011, IEEE Communications Magazine.

[12]  J. Federici,et al.  Review of terahertz and subterahertz wireless communications , 2010 .

[13]  H.B. Wallace,et al.  Imaging Through the Atmosphere at Terahertz Frequencies , 2007, 2007 IEEE/MTT-S International Microwave Symposium.

[14]  C. M. Mann Towards Terahertz Communications Systems , 2001 .

[15]  Shahid A. Khan,et al.  Extra-high frequency line-of-sight propagation for future urban communications , 2003 .

[16]  S. Cherry,et al.  Edholm's law of bandwidth , 2004, IEEE Spectrum.

[17]  L. Andrews,et al.  Laser Beam Propagation Through Random Media , 1998 .

[18]  N. Kukutsu,et al.  10-Gbit/s MMIC wireless link exceeding 800 meters , 2008, 2008 IEEE Radio and Wireless Symposium.

[19]  Zhouyue Pi,et al.  An introduction to millimeter-wave mobile broadband systems , 2011, IEEE Communications Magazine.

[20]  Tadao Nagatsuma,et al.  Giga-bit wireless link using 300–400 GHz bands , 2009, 2009 International Topical Meeting on Microwave Photonics.

[21]  T. Kurner,et al.  The Impact of Reflections From Stratified Building Materials on the Wave Propagation in Future Indoor Terahertz Communication Systems , 2008, IEEE Transactions on Antennas and Propagation.

[22]  D. Penninckx,et al.  The phase-shaped binary transmission (PSBT): a new technique to transmit for beyond the chromatic dispersion limit , 1996, Proceedings of European Conference on Optical Communication.