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OPTICAL PROPERTIES AND POPULATION STATISTICS OF ERBIUM IN OPTICALLY-PUMPED ERBIUM-DOPED ZINC SILICATE GERMANATE WAVEGUIDE AMPLIFIERS

BANERJEE, SIDDHARTHA
http://rave.ohiolink.edu/etdc/view?acc_num=ucin1100892919

Abstract Details

2004, MS, University of Cincinnati, Engineering : Electrical Engineering.
There is a growing need for compact, efficient rare-earth doped waveguide optical amplifiers for use in optical communications. Zn2Si0.5Ge0.5O4 (ZSG) is a promising new host material for Erbium(Er) due to the high concentration of Er which can be incorporated and the high optical activity of the incorporated Er. In this thesis, the absorption and emission cross-sections of Er in Er-doped ZSG are measured both through an analysis of the photo-luminescence spectra, and from direct absorption measurements. Peak cross sections are about 3 x 10-24 m2, comparable to measurements on other oxide-based glass amplifiers. The population statistics of the excited Er-level (4I13/2), along with the excited state lifetime, are determined through a novel rate-equations-based frequency domain method in which the spontaneous emission power at 1534 nm is measured as a function of pump power (980nm) and pump modulation frequency. The determined lifetime of 2ms is comparable to the 2.3ms measured using a conventional pump probe technique. The novel analysis technique yields the Er population statistics and lifetime under different pumping conditions independent of the unknown and variable coupling in and out of the waveguide. This method predicts zero net gain at 70mW, about what is observed. Comparison of calculated gain (based on Er density and measured cross-sections) with measured gains suggest that only about 20-30% of the Er in the material is optically active. Thus, by a systematic study of cross sections, Er population statistics and lifetime, and fraction of optically active Er as a function of Er density, the mechanisms for gain quenching with concentration can be studied. A 4.7cm long sample demonstrated a peak fiber-to-fiber net gain of ~2 dB and a signal enhancement of >13 dB. Cavity characteristics were measured using an analysis of coherent reflection under no pumping. The facet reflectivity was determined to be 0.27 and the scattering/absorption loss was 1.05/cm. These losses, compared with an achievable gain of 0.25/cm under full inversion, suggest that optically pumped lasing at this concentration is not possible. Measurements techniques discussed in this thesis can be used to model and improve other rare-earth based amplifiers.
Dr. David Klotzkin (Advisor)
85 p.
Erbium doped waveguide amplifiers; absorption and emission cross-sections; population statistics; gain dynamics; Erbium excited state life-time; facet reflectivity; waveguide scattering loss; optically pumped lasing

Recommended Citations

Citations

  • BANERJEE, S. (2004). OPTICAL PROPERTIES AND POPULATION STATISTICS OF ERBIUM IN OPTICALLY-PUMPED ERBIUM-DOPED ZINC SILICATE GERMANATE WAVEGUIDE AMPLIFIERS [Master's thesis, University of Cincinnati]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1100892919

    APA Style (7th edition)

  • BANERJEE, SIDDHARTHA. OPTICAL PROPERTIES AND POPULATION STATISTICS OF ERBIUM IN OPTICALLY-PUMPED ERBIUM-DOPED ZINC SILICATE GERMANATE WAVEGUIDE AMPLIFIERS. 2004. University of Cincinnati, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ucin1100892919.

    MLA Style (8th edition)

  • BANERJEE, SIDDHARTHA. "OPTICAL PROPERTIES AND POPULATION STATISTICS OF ERBIUM IN OPTICALLY-PUMPED ERBIUM-DOPED ZINC SILICATE GERMANATE WAVEGUIDE AMPLIFIERS." Master's thesis, University of Cincinnati, 2004. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1100892919

    Chicago Manual of Style (17th edition)

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© 2004, all rights reserved.
This open access ETD is published by University of Cincinnati and OhioLINK.