Title :
Dynamic Range of Frequency Modulated Direct-Detection Analog Fiber Optic Links
Author :
Wyrwas, John M. ; Wu, Ming C.
Author_Institution :
Dept. of Electr. Eng. & Comput. Sci., Univ. of California at Berkeley, Berkeley, CA, USA
Abstract :
A frequency modulated (FM) analog optical link using an FM discriminator is analyzed. Figures-of-merit are derived, including expressions for the second-order (OIP2) and third-order intercept points (OIP3), spurious-free dynamic range (SFDR) and noise figure (NF). It is found that a discriminator with linear field transmission and constant group delay will produce no third-order or higher-order distortions, and balanced detection will suppress the remaining second-order distortion. Low biasing the discriminator is found not to improve the NF of the link. Residual intensity modulation (IM) of the laser is shown to significantly increase the link´s distortion. A discriminator using tenth-order finite-impulse response (FIR) filters implemented in planar lightwave circuits (PLC) is proposed and shown to improve OIP3 by 31 dB over a Mach-Zehnder interferometer (MZI) discriminator.
Keywords :
FIR filters; frequency modulation; integrated optics; intensity modulation; microwave photonics; optical communication equipment; optical distortion; optical filters; optical modulation; radio-over-fibre; FM discriminator; direct-detection analog fiber optic links; figures-of-merit; finite-impulse response filters; frequency modulated analog optical link; group delay; laser residual intensity modulation; linear field transmission; link distortion; microwave-photonic link; noise figure; planar lightwave circuits; radio-over-fiber; second-order intercept point; spurious-free dynamic range; third-order intercept point; Frequency discriminator; microwave-photonic link; optical frequency modulation; optical link; radio-over-fiber;
Journal_Title :
Lightwave Technology, Journal of
DOI :
10.1109/JLT.2009.2031986
