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Variable Bandwidth TIA and Limiting Amplifierfor Maximum Sensitivity in Free Space Optical Links

Reis karimian, Negar | 2013

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 44720 (05)
  4. University: Sharif University of Technology
  5. Department: Electrical Engineering
  6. Advisor(s): Fotowat-Ahmadi, Ali
  7. Abstract:
  8. Nowadays, optical networks is one of the best options for ultra high speed data transmission. An optical network is either implemented using optical fibers or via free space optical links. Fiber optics has gained special popularity among all mediums of data transmission, however, builing a fiber infrastructure is not a cost or time effective solution and this is the main limitation of these networks. Free space optics has been an attractive answer to overcome the drawbacks of the fiber optic networks. On the other hand, atmospheric turbulence and scattering are the main factors affecting FSO’s availability and Reliability. As a result, Design of next generation FSO networks need high speed electronic front-ends with maximum sensitivity to improve the performance. The goal of this M.Sc. Project was the design and simulation of an optical receiver for applications in hybrid FSO/RF links, using a multi-receiver scheme to adapt spatial diversity and a variable BW control unit in 0.18µm CMOS technology. This receiver consists of a Pre-current amplifier, TIA, BW control unit, offset cancellation and a limiting amplifier. The receiver is designed for the data rates of 16Mbps to 1Gbps between the distances of 100m to 1km. Simulation show a total transimpedance gain and input referred noise of 117dB and . Optical sensitivity of the receiver is in the range of -25.2dBm to -43dBm. The total power consumption is 113mW from a 1.8V supply for eight receivers. In this project a state-of-the-art transimpedance amplifier using current summing have been presented. The benefits of this design is high sensitivity and the ability to steer the bandwidth to compensate the channel loss due to the weather. In addition, a novel idea for a new clock data recovery architecture has been proposed which can lock to the data while doubling without losing any of the informations
  9. Keywords:
  10. Limiting Amplifier ; Preamplifier ; Transimpedance Amplifier ; Free Space Optical System

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