Now showing 1 - 6 of 6
  • Publication
    UWB triplet and quadruplet pulses generation employs nonlinear effect in semiconductor optical amplifier nonlinear loop mirror
    ( 2020-01-08)
    Zahari, Suhaila Mohd
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    ; ; ;
    Ghazali N.F.
    ;
    Shahimin M.M.
    Ultrawideband (UWB) triplet and quadruplet pulses generation exploits nonlinear effect in semiconductor optical amplifier (SOA) in nonlinear loop mirror (NOLM) is investigated in this work. Two signals are transmitted through the SOA-NOLM simultaneously to create cross-phase modulation (XPM) effect. Firstly, the XPM causes the production of doublet which later combines for creation of triplet and quadruplet. This technique engages a proper tuning of optical delay and a selection of suitable power in all loops. Besides, injection current of the SOAs also governs the formation of these pulses. Although, frequency of the signals can be varied accordingly, the pulses are limited to certain adjustment that shifted its position in time domain. Furthermore, the set up can also be assessed for monocycle and doublet pulses by extracting the output at several positions. It can be concluded that the design may work as multiple pulses generation. All pulses are examined and compared with their electrical spectrum counterpart for validity of this approach.
  • Publication
    Characterization of all-optical Tofolli and Peres gates employing optimized SOA-NOLM
    In this work, all-optical reversible gates namely Tofolli and Peres are studied and characterized. The gates utilize semiconductor optical amplifier (SOA) in nonlinear loop optical mirror (NOLM). The reversible gates are performed at data rate 10 Gb/s with narrow Gaussian pulses as input signals. Delay of 130 ps and injection current of 170 mA have displayed the optimum outputs in the SOA-NOLM. Extinction ratio is greatly reduced, thus less noise interferes the logic operation in this simple technique. It is observed that Peres gate has shown a higher output power compare to Toffoli gate. This could be due to multiple amplification that are experienced by the signals. Other than the gain, injection current and delay are shown to give major effect in producing the correct bits at the outputs. The SOA-NOLM also can be cascaded for other arithmetic signal processing operation at high frequency. It is also recorded that the design consumes low power especially in small signal gain process. Thus, the design indicates its versatility to be executed in photonic integrated circuits for ultrafast signal control through fiber networks.
      1  39
  • Publication
    Multiwavelength fiber laser employing semiconductor optical amplifier in nonlinear optical loop mirror with polarization controller and polarization maintaining fiber
    ( 2020-01-08)
    Husshini N.F.H.
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    ; ;
    Shahimin M.M.
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    ; ;
    Al-Asadi H.A.A.
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    Raghavendra C.G.
    This paper demonstrates multiwavelength fiber laser employing semiconductor optical amplifier in nonlinear optical loop mirror with polarization controller and polarization maintaining fiber. The configuration consists of a 3-dB coupler, polarization controller and several lengths of polarization maintaining fiber. The results showed a single polarization controller with 5 meters of polarization maintaining fiber length generated 36 of lasing lines at 160mA of semiconductor optical amplifier current. In addition, for the average peak power and average optical signal to noise ratio, the 2 meters of polarization maintaining fiber length with single polarization controller in the nonlinear optical loop mirror shows higher values, 0.55mW at 210mA and 31.98dB at 210mA, respectively. Both gain media have a wider bandwidth operating in the C-band and L-band at room temperature.
      27  1
  • Publication
    An innovative single development process for integrated optical Mach-Zehnder interferometer pattern transfer
    ( 2017-01-01) ;
    Lau Kuen Yao
    ;
    Kang Nan Khor
    ;
    Abdul Wahid M. H.
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    ;
    Vithyacharan Retnasamy
    ;
    Mukhzeer Mohamad Shahimin
    Integrated optical Mach-Zehnder interferometer (IO-MZI) has been widely researched for various usage including for biosensor application. However, the success rate of IO-MZI pattern transfer has been low using the conventional multidevelopment process. One of the main factors is the particle contamination due to the practice of reused developer bath. In this work, an innovative single development process had been proposed with the utilization of the same conventional set-up but with a different protocol. The concept of this method is the estimation of total development time based on the calculated development rate. By doing so, the development process can be completed with only one immersion of the substrate in the developer bath. Besides, the manipulation of development rate by varying exposure time in this work also had revealed the possibility of manipulation of line-width based on the exposure time. In short, the proposed single development process has increased the success rate of IO-MZI pattern transfer from 30% (multi-development method) to 90%.
      32  2
  • Publication
    Characteristics of multiwavelength fiber laser employing semiconductor optical amplifier in nonlinear optical loop mirror with different length polarization maintaining fiber
    In this paper, we propose and demonstrate generated characteristics of a multiwavelength fiber laser based on semiconductor optical amplifier in a nonlinear optical loop mirror with different length of polarization maintaining fiber. The configuration comprises 3-dB optical coupler, semiconductor optical amplifier and, 2 meters and 10 meters of polarization maintaining fiber. Characteristics of multiwavelength fiber laser are studied through the use of polarization maintaining fiber at different lengths. The experimental results revealed the number of lasing lines increases with the increment of the polarization maintaining fiber length. The polarization maintaining fiber with 10 meters of length has the ability to generate a higher number of lasing lines up to 47 signals with semiconductor optical amplifier injected current at 180mA, respectively. However, in terms of average peak power and average optical signal to noise ratio, the 2 meter of polarization maintaining fiber length has the capability to produce a higher value which is 0.45mW at 250mA of semiconductor optical amplifier driven current and 28.86dB at 170mA of semiconductor optical amplifier driven current, respectively. Furthermore, it is observable that this configuration capable to generate a wider bandwidth which is operating in the conventional (C) band to long (L) band at the room temperature.
      37  1
  • Publication
    Critical analysis of stability and performance of organometal halide perovskite solar cells via various fabrication method (Review)
    ( 2017)
    Suriati Suhaimi
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    ; ; ;
    Vithyacharan Retnasamy
    ;
    Mukhzeer Mohamad Shahimin
    Organometal halide perovskite solar cells (Omh-PSCs) have attracted attention due to its unique electrical and optical properties. Ideally, the Omh-PSCs should remain free from degradation under normal operating conditions for several years, preferably tens of years. In order to produce high power conversion efficiency with low potential of degradation, different fabrication methods have been developed. The reported stability of perovskite films can vary significantly and reported to decay substantially up to 20% of its original performance. A thorough understanding of fabrication process upon the stability of the device is regarded as crucial to pave the way for future endeavors. This review summarized and highlighted the recent research of fabrication methods that gave an impact to the stability of perovskite devices.
      1  32