KEYWORDS: Orthogonal frequency division multiplexing, Distortion, Radio over Fiber, Modulation, Modulators, Mathematical modeling, Signal to noise ratio, Nonlinear optics, Radio optics, Interference (communication)
This paper is concerned with the effect of the nonlinearity of an MZM (Mach-Zehnder modulator) on optical OFDM
signal distortion. The optical OFDM signal output from the MZM is expressed as a Taylor series including third-order
and fifth-order nonlinear distortion terms, by which we can easily establish a mathematical model of the optical OFDM
signals in different formats and rates. According to the model, we can get the EVM at the optimized point. Moreover, the
proposed theoretical model is proved in good agreement with experiment results of the RoF (Radio over Fiber) system.
In this paper, a numerical investigation on the nonlinear distortion of OFDM (Orthogonal Frequency Division
Multiplexed) signals caused by RSOA (Reflective Semiconductor Optical Amplifier) as an intensity modulator in
OFDM-PON system is undertaken. Based on curve fitting approach a fourth order polynomial is, for the first time, used
to present the nonlinear gain of RSOA. The expression of in-band and adjacent-band noise due to nonlinear distortion is
then derived. Besides, the EVM of system versus input signal power is simulated by VPItransmissionmaker7.6, the
results indicate the nonlinear effects-induced degradation of transmission performance depends highly on the third order
term of nonlinear distortion power, and the optimum input signal power is provided to improve the transmission
performance. Finally, it's worth mentioning that the quantified analysis method is applicable for the nonlinearity analysis
of any RSOA-Based OFDM-PON system.
The influence of higher-order harmonics produced in modulator on flat and stable optical comb generation based on recirculating
frequency shifter (RFS) for all-optical OFDM is analyzed and demonstrated in this paper. We also
theoretically analyze the condition for flatness of the optical frequency comb. The resulting theoretical analysis is
confirmed by a 16 comb lines and 12.5 GHz spacing RFS generation system. The results demonstrate that flat and stable
optical comb generation based on RFS can be a useful solution for multi-wavelength source in all-optical OFDM.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.