Multi-wavelength laser generation based on nonlinear effects in PCF and Bi-EDF / Roghaieh Parvizi
This thesis describes multi-wavelength laser generation process based on stimulated Brillouin scattering (SBS) and four-wave mixing (FWM) nonlinear effects utilizing photonic crystal fibre (PCF) or/and Bismuth based Erbium doped fibre (Bi-EDF) as the gain medium. Firstly, the threshold power cond...
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Format: | Thesis |
Published: |
2012
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Online Access: | http://studentsrepo.um.edu.my/3818/1/1._Title_page%2C_abstract%2C_content.pdf http://studentsrepo.um.edu.my/3818/2/2._Chapter_1_%E2%80%93_6.pdf http://studentsrepo.um.edu.my/3818/3/3._References.pdf http://pendeta.um.edu.my/client/default/search/results?qu=Multi-wavelength+laser+generation+based+on+nonlinear+effects+in+PCF+and+Bi-EDF&te= http://studentsrepo.um.edu.my/3818/ |
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Institution: | Universiti Malaya |
Summary: | This thesis describes multi-wavelength laser generation process based on stimulated
Brillouin scattering (SBS) and four-wave mixing (FWM) nonlinear effects utilizing
photonic crystal fibre (PCF) or/and Bismuth based Erbium doped fibre (Bi-EDF) as the
gain medium. Firstly, the threshold power condition of SBS for a piece of100 m long PCF
has been theoretically studied in terms of fibre parameters and input pump power. The
threshold exponential gain, Gth, can be anticipated by this simulation which strongly
depends on the fibre length Brillouin gain content and effective area. This value varies from
14 to 18 depending on the fibre length according to the Smith’s definition. The frequency
shift of Brillouin Stokes in the PCF is measured nearly 9.75 GHz via heterodyne
measurement method. In order to reduce the nonlinear fibre length, 49 cm long Bi-EDF is
used, which successfully demonstrates a single wavelength Brillouin Erbium fibre laser
(BEFL) with a peak power of approximately -4 dBm and a side mode suppression ratio
(SMSR) of 14 dB in a ring cavity at fixed Brillouin pump (BP) power of 6 dBm and 1480
nm pump power of 144 mW. A simple multi-wavelength Brillouin fibre laser (BFL) is also
demonstrated using the PCF in conjunction with a fibre Bragg grating (FBG) to produce at
least 7 Stokes and 4 anti-Stokes lines with a line spacing of 0.08 nm. To produce doublespacing
Brillouin lines, a compact multi-wavelength Brillouin fibre laser in conjunction
with a figure-of-eight configuration is proposed. At a BP power of 15.3 dBm, at least 4
simultaneous lines with 20 GHz or 0.16 nm line spacing is achieved by removing the oddorder
Stokes lines. The anti-Stokes lines are also generated via FWM process in the laser
cavity. The output spectrum of the proposed BFL can be tuned by 80 nm, dependent on the
availability of an appropriate BP source. To increase the number of lines and channel
spacing, a multi-wavelength Erbium doped fibre laser (MWEDFL) is demonstrated with incorporating a piece of 215 cm long Bi-EDF through FWM process in a ring
configuration. The proposed laser is able to generate up to 17 lines with a constant channel
spacing of 0.41 nm at L-band region using 147 mW of 1480 nm pump power. The other
stable MWEDFL based on FWM using a hybrid gain media of 100 m long PCF and 49 cm
long Bi-EDF fibre is demonstrated. At a maximum pump power of 1480 nm, 5 lines are
observed with nearly 2.15 nm spacing between the lines, and with a signal to noise ratio of
more than 20 dB. These results show that the use of a highly nonlinear PCF and Bi-EDF is
capable to produce a compact and efficient multi-wavelength laser for many applications
such as wavelength division multiplexing system (WDM) optical communication network
system and sensors. |
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