Interfaces for high speed fiber-optic links: analysis and experiment

TLDR: In this paper, an analysis of directly and externally modulated fiber-optic links is presented, based on the signal flow diagram of the interface circuits to the laser diode, Mach-Zehnder electrooptic modulator, and p-i-n photodiode.

Abstract: An analysis of directly and externally modulated fiber-optic links is presented. The theoretical analysis is based on the signal flow diagram of the interface circuits to the laser diode, Mach-Zehnder electro-optic modulator, and p-i-n photodiode. System parameters such as gain, noise figure, two-tone intermodulation distortion, and spurious free and compression dynamic range are expressed as a function of frequency and operating point of the laser and external modulator. Two directly and externally modulated fiber-optic links were designed and fabricated to verify the analytical models. The direct modulation FO link was developed at the Ku-band (11.6-12.4 GHz), whereas the external modulation link was at L-band (875-925 MHz). Spurious-free dynamic ranges of 95.8 dB Hz/sup 2/3/ and 113 dB Hz/sup 2/3/, respectively, were achieved. The predictions based on the analytical models match the measured results. >