Τίτλος:
Impact of nonlinear LED transfer function on discrete multitone modulation: Analytical approach
Γλώσσες Τεκμηρίου:
Αγγλικά
Περίληψη:
Light-emitting diodes constitute a low-cost choice for optical transmitters in medium-bit-rate optical links. An example for the latter is local-area networks. However, one of the disadvantageous properties of light-emitting diodes is their nonlinear characteristic, which may limit the data transmission performance of the system, especially in the case of multiple subcarrier modulation, which is starting to attract attention in various applications, such as visible-light communications and data transmission over polymer optical fibers. In this paper, the influence of the nonlinear transfer function of the light-emitting diodes on discrete multitone modulation is studied. The transfer function describes the dependence of the emitted optical power on the driving current. Analytical expressions for an idealized link were derived, and these equations allow the estimation of the power of the noise-like, nonlinear crosstalk between the orthogonal subcarriers. The crosstalk components of the quadrature and in-phase subcarrier components were found to be independent and approximately normally distributed. Using these results, the influence of light-emitting-diode nonlinearity on the performance of the system was investigated. The main finding was that systems using a small number of subcarriers and/or high QAM level exhibit a large signal-to-noise-ratio penalty due to the nonlinear crosstalk. The model was applied to systems with white and resonant-cavity light-emitting diodes. It is shown that the nonlinearity may severely limit the performance of the system, particularly in the case of resonant-cavity light-emitting diodes, which exhibit a strong nonlinear behavior. © 2009 IEEE.
Συγγραφείς:
Neokosmidis, I.
Kamalakis, T.
Walewski, J.W.
Inan, B.
Sphicopoulos, T.
Περιοδικό:
Journal of Lightwave Technology
Λέξεις-κλειδιά:
Analytical approach; Analytical expressions; Bit rates; Data transmission; Discrete multitone (DMT) modulation; Discrete multitone modulation; Driving current; In-phase; Large-signals; Light-emitting diode (LED); Multiple subcarrier modulation; Non-Linearity; Nonlinear behavior; Nonlinear characteristics; Nonlinear transfer functions; Optical power; Optical transmitters; Orthogonal subcarriers; Polymer optical fibers; Resonant cavity light emitting diode; Sub-carriers; Subcarrier; Visible light, Computer system recovery; Crosstalk; Current density; Dilatometers; Diodes; Distortion (waves); Light emission; Light transmission; Local area networks; Modulation; Nonlinear distortion; Nonlinear equations; Normal distribution; Optical communication; Optical fibers; Optical links; Optical properties; Photonics; Transfer functions, Light emitting diodes
DOI:
10.1109/JLT.2009.2028903
