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"Parallel-coupled wave-guide with symmetrical structure has interesting coupling characteristics and can be used as multiplexer/demultiplexer when certain working requirements are met. The coupling properties in the coupled wave-guide are analyzed theoretically on the basis of two mode interference effect of the propagating waves, wavelength dependence of wave-guide directional coupler is investigated in the coupling region. A rough approximation of the dependence is determined based on simplified transfer matrix multiplications followed by more detailed computer calculation using Beam Propagation method CBPMI.

By varying the dimensions of wave-guide such as width, thickness, gap, interaction length, refractive index difference and wavelength we could get different coupling properties, then the results of analysis are used to select the appropriate dimensions of multiplexer/demultiplexer that works on the range of wavelength (1.3 pm - 1.6 pm). This burned channel-type directional coupler is designed on Silicon substrate to be fabricated by sputtering technology."

"Characterizations have been performed on single stage Transversely Excited Nitrogen Laser of Blumlein type. Optical cavity arrangement is varied prior to measurement which shows no significant increase in energy on both configurations of inserting a mirror only and a pair of mirror and a quartz parallel plate. Frequency repetitions respond reveals a small drop in energy at higher frequency i.e. 10 Hz by a factor of 20%. N2 flow rate consideration behaves on the similar way like pressure profile. At higher supply voltage maximum energy is shifted to higher N2 flow rate. A similar tendency occurs on pressure curve but with more pronounced maximum energy. Higher supply voltage would shift maximum energy to higher N2 pressure. Other operating conditions have been kept constant. Beam divergence measurement has given 1,87 mrad on vertical direction and 9,32 mrad on horizontal axis. However, beam cross section experiences a -10° tilt against horizontal reference. This may happen due to a slight twist on main electrodes. Measurements on different date have showed inconsistent results. Major cause is suspected on using different N2 cylinder, replacement on the gauge pressure, and crater creation on HV side spark gap electrode."

"ABSTRACTThe molecular weight of Polymer material can be determined using optical system by measuring the intensity of scattered light at low angle light scattering and its the incident beam, based on Rayleigh scattering have developed by Debye has known as Static Light Scattering. To carry out this measurement, an optical system was constructed using a HeNe laser light with a certain intensity, and the light passed through a polymer solution and its scattered light were then detected using a photo multiplier. To obtain the experimental results, the set-up was tested using a polymer standard, which has been already known its average molecular weight. In this experiment were used the polymer standard with average molecular weight 35000, 110000 and 200000. Furthermore, this optical experiment set-up constant, were used for determining the average molecular weight of the polymer samples. In this experiment a linear curve relation between the optical Rayleigh polymer and the polymer concentrations was constructed, and by extrapolating this linear curve up to zero concentration the molecular weight of polymer can be determined. From the laboratory test we got that the experimental set up could be used for the measurement of polymer, which has the molecular weight larger than 35000 to 200000, with tolerance 4 percent."

"Development of optical fiber communication system is mainly due to the progressive influence of optical source. Laser diode as optical source in optical transmission system is of great attention because laser diode produces coherent monochromatic-light. Furthermore, laser diode has a high quantum efficiency, can be modulated at a very high speed, has small size and compact. The application of such optical source is also wide, ranging from optical signal communication to radar optics. Therefore, laser diode is considered to be a key component in optoelectronic system. In this study, an experimental model of analog optical transmission system with laser diode as optical source at wavelength of 0.79 pm has been designed and constructed. The design and construction include optical and electronic circuits. Design description at the wavelength used in this study is briefly described. The characteristics of the system was evaluated by measuring the frequency responds of photo detector, the transmission bandwidth and the loss of the system. The result shows that the frequency responds of the photo detector limits the transmission bandwidth of the whole system. On the other hand, by the use of the selfoc lens for coupling laser diode to fiber line, a coupling efficiency as high Es 55 % has been achieved. Based on the evaluation on the result obtained for the experimental model the practical applicability of the system is pointed out."

"Hydrogenated microcrystalline silicon (Uc-Si:H) thin films have been deposited using 10 % silane (SiH4) in H2 dilution by Hot Wire Cell Very High Frequency Plasma Enhanced Chemical Vapor Deposition (HWC-VHF-PECVD) technique....."

"Teknologi sel surya dewasa ini masih didominasi oleh material berbasis silikon, yang mana memiliki keterbatasan dalam perihal tingginya biaya pada proses produksinya. Dye-Sensitized Solar Cells (DSSC) hardir sebagai alternatif dari sel-surya berbasis silikon atas potensi yang dimilikinya dalam perihal performa fotovoltaik yang stabil dan efisiensi dalam segi biaya produksi. Namun, salah satu komponen utamanya, yaitu fotoanoda berbasis material TiO₂ memiliki keterbatasan dalam perihal penyerapan spektrum cahaya tampak dari sinar matahari secara efisien dan kehadiran cacat yang berasal dari proses sintesis dan deposisi. Sebuah pendekatan menggunakan perlakuan permukaan (surface treatment) fotoanoda TiO₂ dengan larutan kompleks logam transisi diharapkan meningkatkan performa fotovoltaik dari DSSC dengan cara merekayasa struktur pita energi dan keadaan cacat pada fotoanoda TiO₂. Berdasarkan hasil eksperimen yang telah dilakukan, penggunaan perlakuan permukaan fotoanoda TiO₂ dengan larutan kompleks Ni²⁺ menunjukkan peningkatan signifikan terhadap performa fotovoltaik divais DSSC.

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The current solar cell technology is still predominantly dominated by silicon-based materials, which considerably have high production costs. Dye-sensitized solar cells (DSSC) emerge as an alternative to silicon-based solar cells owing to their potential for stable photovoltaic performance and cost-efficient production. However, one of its main components, the photoanode based on TiO₂, has limitations in terms of inefficient absorption of the visible light spectrum from sunlight and the presence of defects generated from the synthesis and deposition process. An approach employing a surface treatment of the TiO₂ photoanode using transition metal complexes solutions is expected to be able to enhance the photovoltaic performance of DSSC by engineering the band structures and defect states of the TiO₂ photoanodes. Our results find that surface treatments of TiO₂ photoanode using Ni²⁺ complex solution via sequential spin coating deposition method enables a significant improvement of the device’s photovoltaic performances."