Optical waveguides – Temporal optical modulation within an optical waveguide – Electro-optic
Patent
1997-03-27
1999-04-06
Ngo, Hung N.
Optical waveguides
Temporal optical modulation within an optical waveguide
Electro-optic
341 57, G02B 610
Patent
active
058928588
ABSTRACT:
A method for encoding a binary input sequence x(0,1) to obtain a duobinary output sequence y(+1,0,-1) is provided. The duobinary coding technique always provides an output bit y.sub.k =0 when the corresponding bit x.sub.k =0; bits y.sub.k alternatively assume a logical level "+1" and "-1" whenever an input bit x.sub.k-1 =0 changes to x.sub.k =1, and the output bit y.sub.k maintains the logical level "+1" or "-1" whenever the corresponding bit x.sub.k maintains the logical level "1". A coding device for encoding a binary input sequence x(0,1) to a duobinary output sequence y(+1,0,-1) is also provided, comprising a D-type flip-flop for generating a binary switch signal. A first AND circuit receives the input sequence and the switch signal, and provides a first binary sequence a(0,1), while a second AND circuit receives the input sequence and the complement of the switch signal and provides a second binary sequence b(0,1). These first and second binary sequences are applied to a summer to obtain the output sequence y(+1,0,-1). A method for differentially driving a M-Z modulator using a virtual ground level is also provided, which reduces the peak-to-peak drive voltage by a factor of two.
REFERENCES:
patent: 4244051 (1981-01-01), Fujikura et al.
patent: 4910750 (1990-03-01), Fisher
patent: 5002353 (1991-03-01), Johnson
patent: 5015053 (1991-05-01), Johnson
patent: 5408500 (1995-04-01), Ginzburg et al.
Steve Ross: "Unipolar/bipolar circuit eases data flow", E.D.N: Electrical Design News, vol. 30, No. 22, Nov. 1985, p. 208.
Yonenaga K. et al: Optical Duobinary Transmission System with no Reciver Sensitivity Degradation Electronics Letters, vol. 31, No. 4, Feb. 16, 1995, pp. 302-304.
Gu X et al: 10 GBIT/S Unrepeatered Three-Level Optical Transmission Over 100 KMOF Standard Fibre Electronics Letters, vol. 29, No. 25, Dec. 9, 1993, pp. 2209-2211.
May et al., "Extended 10 Gb/s Fiber Transmission Distance at 1538 nm Using a Duobinary Receiver", IEEE Photonics Technology Letters, vol. 6, No. 5 (1994).
Price et al., 210 km Repeaterless 10 Gb/s Transmission Experiment Through Nondispersion-Shifted Fiber Using Partial Response Sheme, IEEE Photonics Technology Letters, vol. 7, No. 10 (1995).
Price et al., "Reduced bandwidth optical digital intensity modulation with improved chromatic dispersion tolerance", Electronics Letters, vol. 31, No. 1 (1995).
Yonenaga et al., "Optical duobinary transmission system with no receiver sensitivity degradation", Electronics Letters, vol. 31, No. 4 (1995).
O'Sullivan Maurice S.
Roberts Kim Byron
Solheim Alan Glen
Taraschuk Terry W. B.
Vaziri Mazoud
Ngo Hung N.
Northern Telecom Limited
LandOfFree
Duobinary coding and modulation technique for optical communicat does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Duobinary coding and modulation technique for optical communicat, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Duobinary coding and modulation technique for optical communicat will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1378607