M.A.M. Azidin

Correlation of Brillouin Stokes Signals and Optical-Signal-to-Noise-Ratio in Multi-Wavelength Brillouin Fiber Laser with Additional Fiber Bragg Grating

We experimentally demonstrate unidirectional propagation of multi-wavelength Brillouin fiber laser system with additional fiber Bragg grating. The configuration is arranged in a ring resonator by utilizing five different Brillouin gain mediums. In this experiment, the input Brillouin pump power was varied in order to maximize the generated Brillouin Stokes signals based on the respective fiber lengths. The influence of these controllable parameters leads to the correlation between of Brillouin Stokes signals and optical-signal-to-noise-ratio. In this case, at 10 km of single mode fiber the maximum of 38 Brillouin Stokes signals were generated together with 15.07 dB of average optical-signal-to-noise-ratio when the 17 dBm Brillouin pump power was launched into the ring resonator.

All-Optical XOR Logic Gates: Insights and Comparisons

Three XOR photonics logic gate configurations namely semiconductor optical amplifier-Mach Zender interferometer cross phase modulation (SOA-MZI XPM), SOA-MZI cross gain modulation (XGM) and terahertz optical asymmetrical demultiplexer (TOAD) XOR are analysed and compared in terms of generated power, optical signal-to-noise ratio (OSNR) values and bit error rate (BER) signal quality. The highest generated power is possessed by the TOAD at 23.5 dBm, the SOA-MZI XPM showed the most extinction ratio or OSNR with 109.6 dB whereas the best BER is recorded in the SOA-MZI XGM at 4.42 x 10-22.

Fiber Length Optimization of Ring Cavity Multi-Wavelength Brillouin Fiber Laser Utilizing Fiber Bragg Grating

In this paper, we experimentally investigated the performance of ring cavity multi-wavelength Brillouin fiber laser utilizing fiber Bragg grating which operated in the C-band wavelength region. The combination of stimulated Brillouin scattering and selective wavelengths gave a new invention in the optical fiber communication. Five different lengths of single mode fiber are used in order to get the best gain medium for stimulated Brillouin scattering effect. Up to 33 of Brillouin Stokes signals and 31 of anti-Stokes signals were obtained when 10 km fiber length was used in the laser system. The average value optical signal to noise ratio of 15 dB has been achieved. The broadening bandwidth of Brillouin Stokes signals also occurred at the center wavelength of 1550 nm based on the 3 dB bandwidth of 5 nm fiber Bragg grating.

Optimization of Output Coupling Ratio for Multi-Wavelength Brillouin Fiber Laser Employing FBG and DCF as Gain Medium

A ring-cavity multi-wavelength Brillouin fiber laser by employing a fiber Bragg grating and dispersion compensating fiber was experimentally demonstrated. The multi-wavelength Brillouin fiber laser has been analyzed at different output coupling ratios at 1550 nm of Brillouin pump wavelength. A ring-cavity multi-wavelength Brillouin fiber laser has been designed with a 16 km long of dispersion compensating fiber which acts as gain medium for stimulated Brillouin scattering effect. Dispersion compensating fiber is designed to have small core size and has higher nonlinear coefficient. As a result, 8 Brillouin Stokes signals were produced at maximum Brillouin power of 21 dBm and output coupling ratio of 80%. The best performance of output coupling ratio was determined by 70% with the highest of signal to noise ratio at 38.39 dB.

High Speed All-Photonic Flip-Flop Operation at a Single Wavelength

This work is based on dual Mach-Zehnder interferometer with semiconductor optical amplifiers in both arms. The proposed flip-flop operates at a single wavelength. A bidirectional coupler is placed at the end of the system to observe the output at set and reset terminals. The signals modulate the injected photon rate in the SOAs thus forming photonic flip-flop function. The photon injection rate is modulated due to self-gain modulation and self-phase modulation that occur in the SOAs towards demonstrating optical bistability. Switching between states of the flip-flop occur at full width half maximum of 32 ps. The output power of this flip-flop is around 24.5 mW. It is observed that the switching energy can be adjusted to a low level by decreasing the injected currents into the SOAs. The injection and the input power are the two parameters that govern the whole operation of the designed flip-flop.

S-shaped S-band multi-wavelength Brillouin Raman Fiber Laser employing Raman amplifier

The simulation demonstrated an S-shaped multi-wavelength Brillouin-Raman Fiber Laser employing Raman amplifier in the cavity. Raman amplifier- average power model is employed for signals amplification. This configuration is operated in the S-band wavelength region with tuning range between 1460 nm to 1530 nm. A laser signal at 1500 nm with 4 dBm of output power act as the Brillouin pump, while at output power of 90 mW with 1425 nm of wavelength act as the Raman pump. As a result, at 10 km of single mode fiber and output coupling ratio of 90%, 7 outputs of Brillouin Stokes signals are obtained with maximum output power of 33.88 dBm. Meanwhile, maximum gain values at 38. 07 dBm is recorded at 90 mW of injected Raman pump power. It is notable that the Raman gain broadening occurs around 1500 nm to 1530 nm in S-band wavelength region.

Current density of carriers and emission rate in zinc selenide LED

This work is based on the development of LED using a circular chip of ZnSe. Proper analyses of the proposed LED are performed by adding optical transition and nonradiative recombination processes. The voltage applied to the ZnSe LED ranges from 0 V to 3.5 V. The current-voltage characteristic and the flow of current density are obtained. At 2.5 V, the carriers move towards n-contact hence reduces the internal quantum efficiency. The carriers are observed to drift in opposite direction of the electric field until recorded voltage of 3.5 V where both carriers in line with the electric field. The emission at low voltage in p-layer is localized and caused the efficiency to reduce considerably.

Metal oxide based surface acoustic wave sensors for fruits maturity detection

This work focuses on the effectiveness of different metal oxides act as sensing layer in the gas sensor. This is for sensing ethylene (C2H4) gas in fruit ripening detection. The study involved a computational approach, COMSOL Multiphysics whereby the ripeness detector is simulated and characterized. The paper presents a sensitives layer of metal oxides with a thickness of 0.5pm on Lithium Niobate (LiNbO3) piezoelectric substrate for ethylene (C2H4) gas sensing application in order to distinguish maturity level of fruits. The optimum operational frequency is found to be 867MHz by choosing Zinc Oxide (ZnO) as the sensing layer. This paper presents a two-dimensional simulation of Surface Acoustic Wave (SAW) wave propagation, plus this simulation will help in understanding more on the behavior and the most efficient sensing layer material to be used as the gas sensor without having to perform the actual fabrication process.

Two-photon absorption and free-carrier effects in semiconductor optical amplifier

This paper presents the carried out investigation on nonlinear effects in semiconductor optical amplifier (SOA); in particular two-photon absorption process and its induced free carriers. The simulation results show nonlinear phase shift and the spectral broadening is induced by nonlinear free-carrier effect after propagation through the SOA. The levels of injected carrier density in SOA are varied to find the minimum BER. It is observed that increasing the injection current will result in better BER as the injected current increases until 1A, the quality of eye pattern is better and widely open with minimum recorded BER is 0.

Effect of dopant thickness variation in zinc oxide infrared LED

This paper presents investigation carried out on the properties of zinc oxide (ZnO) infrared light emitting diode (IR LED). Specifically, it focuses on dopant thickness variation in n and p layers. The IR LED structure is designed based on simple p-n junction theory. The p contact is deposited on the center top, and n contact is deposited at the edge of the IR LED. Thus, a current-voltage relationship and internal quantum efficiency with a variation of dopant thicknesses can be studied. Turn-on voltage is highly dependent on the dopant concentration. It is observed that 5 pm p-doped produces a more spatial distribution of the radiative emission compared to others. Moreover, 8 pm p-doped shows result of zero efficiency droop. IQE result also indicates the effectiveness of IR LED operation whether by using low or high current. Finally, the properties of ZnO IR LED are summarized and concluded.