Plasmonic demodulation is a process where an optical signal due to the generation of surface plasmon polaritons (SPP) reacts with electrical domain, resulted an inverse relationship between them. In this study, fabrication processes of gold strip thin films on the glass substrates are presented. For an optimization purpose of electro-optics effect observation, the width of gold strip thin film is set as 0.5mm, which is equal to the laser beam spot diameter. First, the strip pattern is printed on a commercial transparent plastic slide. The pattern transfer process from plastic slide to glass slide is performed using UV light. Once the pattern is formed on the glass substrate, gold thin film with varies thicknesses namely 30nm, 50nm and 100nm are deposited by monitoring the sputtering time; via d.c. sputtering on the glass substrate which is partly coated with the positive photoresist. The photoresist is removed by immersing the coated glass slide in acetone solution for 15 minutes, follow with DI water for three seconds in an ultrasonic bath. This yields to the establishment of gold strip thin films with dimension of width 0.5mm x length 10mm. An optimal plasmonic demodulation process is successfully acquired by using gold metal strip with thickness of 30nm and higher laser power level, namely P=1.5mW. In a conclusion, we believe that the output of this study will contribute a significant impact to the development of the plasmonic demodulator as an active device.

Optical sensor based on surface plasmon resonance are widely used for various applications. In this paper, an optimization of EM waves polarization modes for the occurrence of SPR by using a modified optical waveguiding assembly has been discussed. A 633 nm of linearly polarized He-Ne laser was appointed as a light source. The polarization modes were controlled by rotating the position of He-Ne laser. It was found that the optimum SPR signal with reflectance, R = 0.21 a. u and SPR angle, theta(SPR) = 48 degrees can be obtained as the position of laser was rotated at 90 degrees, with the presence of polarizer. The location of the critical angle was observed at theta(C) = 46 degrees. For the validation purpose, a simulation based on Fresnel equation was conducted where the percentage difference between the experimental and theoretical results were analyzed. The percentage difference between experimental and theoretical results for both theta(SPR) and theta(C) were 9.09% and 15.00% respectively. In conclusion, an excellent agreement between the theoretical and experimental findings proved the stability of this SPR setup, where the EM waves polarization can easily be controlled by manipulating the position of laser.

In recent years, there has been a significant interest in the development of optical waveguide modulators using Silicon-On-Insulator (SOI) substrates motivated by the potential to provide a reliable low-cost alternative to other photonic materials. Objective: In this paper, Multimode Interference (MMI) device is used to develop the MZI structure of the optical modulator. Meanwhile, the electrical part of the modulator utilizes the forward biased P-I-N structure. The effect of varying MMI width to the performance of the MZI optical modulator on SOI was investigated. The effect of varying MMI width to the insertion loss (IL), extinction ratio (ER) and modulation efficiency (V pi L) of the device were carried out. Results: The investigated MMI widths are 22, 30 and 38 mu m. Smallest MMI width, which is 22 mu m has recorded the lowest value of insertion loss with 3.30 dB and the best extinction ratio of 25.60 dB. However, the best modulation efficiency was observed for the MMI width of 38 mu m with 0.1696 V.cm. Conclusion: Appropriate selection of MMI width is vital to ensure optimum performance of the MZI modulator.