Plasma enhanced chemical vapor deposition of low-loss as-grown germanosilicate layers for optical waveguides

Date
2004
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Source Title
Proceedings of SPIE Vol. 5451, Integrated Optics and Photonic Integrated Circuits
Print ISSN
0277-786X
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Publisher
SPIE
Volume
5451
Issue
Pages
511 - 517
Language
English
Type
Conference Paper
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Abstract

We report on systematic growth and characterization of low-loss germanosilicate layers for use in optical waveguides. Plasma enhanced chemical vapor deposition (PECVD) technique was used to grow the films using silane, germane and nitrous oxide as precursor gases. Chemical composition was monitored by Fourier transform infrared (FTIR) spectroscopy. N-H bond concentration of the films decreased from 0.43 ×1022 cm -3 down to below 0.06x 1022 cm-3, by a factor of seven as the GeH4 flow rate increased from 0 to 70 seem. A simultaneous decrease of O-H related bonds was also observed by a factor of 10 in the same germane flow range. The measured TE loss rates at λ=632.8 nm were found to increase from are 0.20 ± 0.02 to 6.46 ± 0.04 dB/cm as the germane flow rate increased from 5 to 50 seem, respectively. In contrast, the propagation loss values for TE polarization at λ-1550 nm were found to decrease from 0.32 ± 0.03 down to 0.14 ± 0.06 dB/cm for the same samples leading to the lowest values reported so far in the literature, eliminating the need for high temperature annealing as is usually done for these materials to be used in waveguide devices.

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Keywords
FTIR, Germanosilicate, Optical loss, Optical waveguides, PECVD, Prism coupling, Germanium compounds, Light polarization
Citation
Published Version (Please cite this version)