Hui-juan ZHOU(周会娟), Zhou MENG(孟洲), Yi LIAO(廖毅)
College of Optoelectronic Science and Engineering, National Unive rsity of Defense Technology, Changsha 410073, China
Abstract-The modulation depth, defined according to practical modulation results, which changes with the microwave power and its frequency, is significant for systems utilizing the frequency-shift characteristic of the Li NbO3 waveguide Electro-Optic Intensity Modulator (EOIM). By analyzing the imp edance mismatch between the microwave source and the EOIM, the effective voltage applied to the RF port of the EOIM is deprived from the microwave power and its frequency. Associating with analyses of the phase velocity mismatch between the microwave and the optical wave, the theoretical modulation depth has been obtai ned, which is verified by experimental results. We provide a method to choose th e appropriate modulation depth to optimize the desired sideband through proper t ransmission bias for the system based on the frequency-shift characteristic of the EOIM.
Key Words: LiNbO3 waveguide electro-optic intensity modula tor; modulation depth; frequency shift; distributed Brilouin optical fiber sensi ng
Manuscript Number: 1674-8042(2010)02-0125-04
dio: 10.3969/j.issn.1674-8042.2010.02.06
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