Indium tin oxide-based Q-switched fiber laser generation and sensing application
A pulsed fiber laser has gained significant attention due to widespread and useful photonics applications in the fields of high-speed communications, optical imaging, and material processing. Q-switching and mode-locking are two possible pulse fiber lasers that can be generated using active an...
Main Author: | |
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Format: | Thesis |
Language: | English English English |
Published: |
2021
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Subjects: | |
Online Access: | http://eprints.uthm.edu.my/3932/1/24p%20NOOR%20UMMI%20HAZIRAH%20HANI%20ZALKEPALI%20%40%20ZULKEFLI.pdf http://eprints.uthm.edu.my/3932/2/NOOR%20UMMI%20HAZIRAH%20HANI%20ZALKEPALI%20%40%20ZULKEFLI%20COPYRIGHT%20DECLARATION.pdf http://eprints.uthm.edu.my/3932/3/NOOR%20UMMI%20HAZIRAH%20HANI%20ZALKEPALI%20%40%20ZULKEFLI%20WATERMARK.pdf |
Summary: | A pulsed fiber laser has gained significant attention due to widespread and useful
photonics applications in the fields of high-speed communications, optical imaging,
and material processing. Q-switching and mode-locking are two possible pulse fiber
lasers that can be generated using active and passive techniques. The active technique
requires a bulky and complex modulator, but the passive technique uses only a piece
of a nanomaterial as a saturable absorber (SA) to induce loss modulation in laser
configurations. In this regard, the active material of indium tin oxide (ITO) was used
to build a SA device through DC magnetron sputtering in generation Q-switched pulse
erbium-doped fiber laser (EDFL). ITO was never used for tuning wavelength with an
intra-cavity filter and the application of pulse fiber laser such as a sensor. Two different
implementation methods of ITO were successfully fabricated and characterized for Q�switching. The first ITO was deposited onto fiber ferrules to observe the performances
of Q-switched pulse EDFL using various configurations such as linear, single ring, and
Figure-8 cavities that have the repetition rate of 18.20 kHz, 38.03 kHz, and 24.19 kHz,
respectively. Thus, the single ring configuration was selected and improved to enable
Q-switched wavelength tunability by employing a tunable bandpass filter (TBF). The
tunable Q-switched pulse EDFL wavelength was operated from 1540.0 nm to 1570.0
nm. The generated output pulses displayed a repetition rate of 94.34 kHz and the
shortest pulse width of 3.22 µs at the maximum pump power of 378.6 mW. Next, the
stable switchable dual wavelength was generated by the aid of two selected fiber Bragg
gratings in the single ring cavity. To achieve a flexible switched in individual
wavelength of 1532 or 1533 nm and a simultaneous dual-wavelength fiber laser, the
in-line polarization controller had to be adjusted. The second device implemented onto
the side-polished fiber, coated with ITO (SPF-ITO), had generated as a novel method
for Q-switching and ammonia sensor. The SPF-ITO was successfully utilized as the
SA as well as a sensor for monitoring different concentrations of the ammonia solution.
The pulsed fiber laser ammonia sensor can be observed through the shifts in
wavelength and frequency domain due to the interactions between the ammonia molecules and ITO thin film where the SPF-ITO was immersed in the ammonia
solution. The shifts of wavelength from 1558.45 nm to 1554.25 nm resulted from the
increase in ammonia concentrations from 0.5 x 105
to 3.0 x 105
ppm. The wavelength
shifted from 1561.30 nm to 1559.35 nm using an increased concentration of ammonia
from 1 to 10 ppm. Meanwhile, the shifts of RF signal from 35.50 kHz to 43.50 kHz
were the result of the change in ammonia concentrations from 0.5 x 105
to 3.0 x 105
ppm. The RF signal shifted from 30.10 kHz to 33.70 kHz in tandem with the increase
of ammonia concentrations from 1 to 10 ppm. In brief, the SPF-ITO was successfully
fabricated for the Q-switcher as well as the sensor |
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