Amplification of light in sol-gel-based Nd-glass waveguides

S. R. Natarajan; Anand V. Ramamurthi; Ananth Selvarajan; M. Muthuraman; K. C. Patil

doi:10.1117/12.305397

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15 April 1998 Amplification of light in sol-gel-based Nd-glass waveguides

S. R. Natarajan, Anand V. Ramamurthi, Ananth Selvarajan, M. Muthuraman, K. C. Patil

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Proceedings Volume 3280, Rare-Earth-Doped Devices II; (1998) https://doi.org/10.1117/12.305397
Event: Optoelectronics and High-Power Lasers and Applications, 1998, San Jose, CA, United States

Abstract

Integrated optic planar waveguides fabricated by sol-gel method by doping Neodymium (Nd³⁺) in glass were studied for gain properties. To our knowledge, this is the first time that a theoretical model based on atomic susceptibility (χ_as) is applied to the study of sol- gel based Nd-glass waveguide amplifier. Single pass amplification through these waveguides using this theory correlates well with the experimental results. As we see a strong dependence of χ_as in the observed gain coefficient, it is also possible to extend this theory to the case of inhomogeneously distributed Nd-atomic clusters in the gain medium. Studies on the absorption spectra of the samples showed a strong peak at λ equals 585 nm, which was used as the wavelength for pumping the waveguide. We note that a net gain of over 15 dB is achievable over a few cm's of the waveguide, assuming a homogeneous dispersion of the dopant ions in the medium. The precursors for the sol were TEOS (Tetraethyl orthosilicate) and TPOT (Titanium(IV) isopropoxide) in the ratio of 4:1 and Nd₂O₃ was used as the dopant. The concentration of the Nd³⁺ in the waveguide was 2.5 at. %. On a clean glass substrate, with typical dimensions of 2 cm x 1 cm, spincoated films comprising of multi-layers, produced a thickness of approximately 4 micrometers and a refractive index change of 0.0476 as revealed by the m-line measurements using the prism coupling technique. The samples supported two modes at λ=633 nm.

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S. R. Natarajan, Anand V. Ramamurthi, Ananth Selvarajan, M. Muthuraman, and K. C. Patil "Amplification of light in sol-gel-based Nd-glass waveguides", Proc. SPIE 3280, Rare-Earth-Doped Devices II, (15 April 1998); https://doi.org/10.1117/12.305397

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