Graphical Approach for Evaluating Performance Limitations in Externally Modulated Analog Photonic Links
ABSTRACT We present a novel graphical approach for evaluating the performance of analog photonic links employing an external intensity modulator biased at quadrature. A single graph is sufficient to grasp the engineering tradeoffs among noise figure, third-order spurious-free dynamic range, and RF gain for various values of half-wave voltage and dc photocurrent.
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ABSTRACT: Free-space optical (FSO) links typically carry digital data over short to moderate distances (100m - 50 km). From a military perspective, FSO links have the advantages of low probability of interception, inherent anti-jam capability and a reasonable degree of covertness. In certain applications it is desirable to minimize size, weight and power of the transmitter and this pushes the designer to eliminate power-hungry digitizers and to transmit raw analog, instead of digital, information. However, the transmission of analog signals presents significant technical challenges due to strong fluctuations in received optical power resulting from atmospheric turbulence. In this case the standard RF link properties of gain, noise factor, and linearity must be described entirely in statistical terms. In this paper we present preliminary experimental results from a short (500m), single-tone, 5 MHz analog FSO link and compare the data to theoretical predictions. Theory suggests, and our preliminary experimental results confirm, that the statistical properties of all the RF performance metrics of a FSO analog link are determined entirely by the statistical properties of the received optical power. We show that the distribution of values of RF link parameters can be obtained directly from the distribution of received optical power, without the need for modeling the received power with a continuous function.Proc SPIE 05/2009;
Conference Paper: Developments in high performance photodiodes[Show abstract] [Hide abstract]
ABSTRACT: As the current handling - bandwidth product of a single photodiode comprised of lattice matched In0.53Ga0.47As/InP material reaches a practical limit, we explore new lattice mismatched material system of In0.72Ga0.28As/InAsP/InP as a path-forward technology to increase this key parameter.Photonics Conference (IPC), 2012 IEEE; 01/2012
Conference Paper: Long-haul analog links tutorial[Show abstract] [Hide abstract]
ABSTRACT: Presents a collection of slides covering the following topics: analog versus digital fibre optics; applications of long-haul RF photonics; components and IMDD metrics; single channel fibre effects; alternate modulation format; transmitter linearization techniques; and photodiode nonlinearities.Optical Fiber Communication (OFC), collocated National Fiber Optic Engineers Conference, 2010 Conference on (OFC/NFOEC); 01/2010