M.Ing. / Bragg gratings are important components for sensing and for wavelength-division multiplexed optical communication systems. These gratings are manufactured by either side-writing of the fiber with a high intensity UV light through a phase mask, or by exposing the fiber to interference fringes through an interferometer arrangement. With one phase mask, only a small range of grating wavelengths is possible. This is achieved by pre-straining the fiber during the writing process. The limitation arises from the break strength of the fi ber, allowing a maximum range of Bragg wavelengths of only approximately 10 nm. The interferometric technique uses a beam splitter to divide a single input UV beam into two and intersecting them at the fiber. The angle at which the beams intersect will determine the period of the interference fringes and thus the Bragg grating written in the optical fiber. The Argon-ion laser is used with a 1060 nm phase mask (used to split beam) to write Bragg gratings with reflections from 1012 to 1600 nm. Three accurate- translation and rotation stages are used to keep the fiber at the beam intersection. Alignment, mechanical stability and coherence of laser are critical.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:uj/uj:2503 |
| Date | 06 June 2012 |
| Creators | Du Toit, Ruan W. |
| Source Sets | South African National ETD Portal |
| Detected Language | English |
| Type | Thesis |
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