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Time filter

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Sarmani A.R.,University Putra Malaysia | Sheih S.-J.,Taiwan International Securities Group | Mahamd Adikan F.R.,University of Malaya | Mahdi M.A.,University Putra Malaysia
Chinese Optics Letters | Year: 2011

Spectral hole burning (SHB) effects in a gain-flattened erbium-doped fiber amplifier (EDFA) are demonstrated to be significant in the presence of large signal power around the 1530-1532-nm wavelength range. These are the first effects reported in a setup employing equivalent power level distribution of 40 channels ranging from 1530 to 1561 nm. To explain this, the introduction of a new local population variable into the laser equation is required to support the original inversion ratio that is determined by the pump lasers. In the analysis section, spectroscopic parameters and high signal powers are considered to be other contributing parameters to the change in the gain characteristics. An improvement to this theoretical basis is suggested by implementing mathematical modeling to validate similarities between the gain shape of simulation to that obtained in the experiment. © 2011 Chinese Optics Letters. Source


Sarmani A.R.,University Putra Malaysia | Sheih S.-J.,Taiwan International Securities Group | Mahamd Adikan F.R.,University of Malaya | Mahdi M.A.,University Putra Malaysia
Laser Physics | Year: 2010

We demonstrate the effect of inversion population ratio mediated by 980 nm pumping band on the gain spectra of a gain-flattened Erbium-doped fiber amplifier. The gain equalizing filter was designed at 977 nm and the amplifier was built in the four-stage arrangement. In the pumping structure, the 1480 nm lasers were maintained in the final gain block while the 980 nm band lasers were utilized in the first three blocks. These laser sources were arranged at several combinations of 977 and 980 nm wavelengths. Within these 3 nm spectrum, an absorption cross-section difference around 0.32 × 10-25 m2 contributed to a dispensable gain variation up to 3-dB. These inequalities were the results of variations in population inversion induced by the pump wavelength discrepancy. The findings show the importance of designing a filter at the specific absorption wavelength to allow the operation of consistent gain level. © 2010 Pleiades Publishing, Ltd. Source


Abu Bakar M.H.,University Putra Malaysia | Sheih S.J.,Taiwan International Securities Group | Mahamd Adikan F.R.,University of Malaya | Mahdi M.A.,University Putra Malaysia
Laser Physics | Year: 2011

This is a study on the design of variable gain-flattened erbium-doped fiber amplifier operating in L-band transmission window. Four amplifiers divided into five stages became the basis of the design with distributed pumping configuration. A dispersion compensating module was incorporated into the architecture as a way to combat dispersion. The amplifier was able to generate variable gain from 15 up to 30 dB under different input signal powers with a maximum output power of 23 dBm. Excellent gain flatness averaging around 0.8 dB was accomplished while four-wave mixing effect was significantly reduced. © 2011 Pleiades Publishing, Ltd. Source


Yusoff N.M.,University Putra Malaysia | Yusoff N.M.,University of Technology Malaysia | Abu Bakar M.H.,University Putra Malaysia | Sheih S.J.,Taiwan International Securities Group | And 2 more authors.
Laser Physics | Year: 2010

Erbium-doped fiber amplifier with flat gain over 30 nm bandwidth is demonstrated using flexible selective band methods. The band optical amplifier was designed to cater 44 wavelength division multiplexing channels which were separated into bands of 4 nm. Without using any gain flattening filter, the gain of optical amplifier was maintained at 19 dB with a maximum gain variation of less than 1.6 dB even though the input signal power was varied from -19 to -6 dBm. The amplifier was able to maintain 1 dB gain flatness with 83% chance for any selective bands of 4 nm within the wavelength range from 1530 to 1565 nm. This feature is very attractive to support band optical networks. © 2010 Pleiades Publishing, Ltd. Source

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