Diode lasers have many advantages such as small size, high efficiency and small
angular dispersion of the collimated beam. However they also have some problems like
lack of frequency stability. They can not be tuned in wavelength. An external cavity can
solve these problems and decrease the laser linewidth.
To obtain a tunable, narrow linewidth light source, antireflection coatings were
applied to commercial diode lasers which were then tested in an external cavity. Laser
characteristics, such as threshold current, spectral behavior, I-V-curves, tuning range, and
bandwidth were measured for the original diode laser and then compared to the
measurements in an external cavity with and without antireflection (AR) coatings. The
tuning range approximately doubled after AR coating. The modal stability was found to be
better by a factor of 7 in the external cavity. The power amplification through the external
cavity was as high as 50.
It was also attempted to process laser diodes from material fabricated at OSU,
however the resulting diodes showed a high series resistance and were not usable for this
project. Additional work needs to be done in this area.
The result of this work is a stable external cavity diode laser tunable over an 18 nm
bandwidth which can be used as a tunable source in many applications. / Graduation date: 1995
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/35280 |
| Date | 19 December 1994 |
| Creators | Falconer, Beate Stephan |
| Contributors | Plant, Thomas K. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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