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"ABSTRACTA non-mechanical method of measuring temporally coherent light, which may be dominated by incoherent background radiation, has been developed. The measurement method is based on the modulated signal produced by the temporally coherent radiation through a LiTaO3 crystal. In the study, the coherent and incoherent lights are combined. To detect coherent light in the presence of incoherent radiation, the crystal is modulated with 2 KHz to 25 KHz sinusoidal signals. To obtain good modulation, the crystal is biased with 150-volt dc. By observing the detector output, it can be seen that only the crystal modulates the coherent light is modulated by crystal."

"An optical modulation by the use of bending effect developed from the effect of relative bending loss on optical fiber. The bending loss will decrease if the bending angle decreases. By varying the bending angle the bending loss will vary too. The modulation process obtained through this mechanism. The bending angle on optical fiber obtained from three mandrel laid on the loud-speaker; two mandrel on the frame and one on the cone of loud-speaker, while optical fiber laid between the mandrel. If current signal injected on coil loudspeaker, the coil will push the mandrel and then push optical fiber to form bending angle. The obtained 3 dB frequency response ranged from 28 Hz to 5714.3 Hz while the SNR and modulation index are 32.98 dB and 0.956 respectively. This modulator would be useable for single channel instrumentation and control links."

"With the growth of optical communications using Low toss optical. fibers. the need for an optical switching system that exchanges optical. signals without any optoelectric and electro optic converter may arise. In this study, an experimental model of sliding prism switch using planar micro lens array has been constructed. The performance of the constructed switching device was studied by measuring insertion Loss. coupling efficiency and cross talk. The experiment shows that the measured results of insertion losses that is 6 and 7 dB are greater than the theoretically calculation that is 1.3 dB. The modulated signal has been measured as we t t ; the shape of the signal does not change after passing through the switch and on the other hand the amplitude of the output signal. is tower than the input signal due to the transmission Loss. I t is concluded that the experimental model of sliding prism demonstrate the potential application of planar micro lens in optical switch device."

"A design of novel optical power divider with tapered coupled wave-guide structure is proposed. The structure of optical power divider is directional coupler, which consists of parallel tapered wave-guide. The device was designed and its feature was simulated by the beam propagation method (BPM). Unique power coupling characteristics are demonstrated. A special case of a 1 x 3 Optical Power Divider has been designed. Simulation of the output power distribution at a wavelength of 1.31 μm shows the discretionary splitting ratio 0.32: 0.33: 0.35 for interaction length longer than 3 mm."

"ABSTRAKIn transmission system, the information to be transmitted from one source to several addressed receivers requires a component to distribute the information. To achieve an efficient and simple distribution circuit of information, a study on the use of fiber as information signal distributor without using other optical elements has been developed as a fiber star-coupler. The optical fiber star-coupler was constructed by chemically processing the end face of fiber into a cone-shaped. The process was carried out by chemical treatment for unjacketed fibers using HF solution. The optical signal distributed to the outgoing fibers will have as higher intensity as the nearer the fiber to the optical axis. An efficient fiber star-coupler can be achieved by arranging the optimum number of receiving fibers correspond to coupling distance and numerical aperture of the optical fibers."

"ABSTRACTIn optical communication system, optical star coupler devices are important for distributing optical signal from one incoming fiber into several outgoing fibers. In this research, an investigation on the design of optical fiber star coupler has been carried out by the use of simple way. Utilizing the cone-shaped end face of several fibers as receivers, optical star coupler has been constructed without using any optical element .An experiment to examine the efficiency of coupling light power from an incoming fiber to seven outgoing fibers has been excetited. The measurement shows that each sample of set outgoing fibers receives an equal amount of light power, which means that the individual coupling efficiency of respective outgoing fibers is equal. Therefore, it is concluded that the proposed star coupler is applicable to be utilized for distributing a light signal to several output terminals."

"ABSTRAKSpecific performance of an optical waveguide can be achieved by solving the eigen value equation of the respective waveguide. A numerical method to obtain dispersion characteristics of a planar waveguide has been executed on a computer program which run on IBM PC or its compatible with 640 KB memory. Coupler prism method was used to measure the waveguide parameters. A focused beam of TE or TM polarized mode of He-Ne laser light is fed into the prism and enters the film of the waveguide. At coupling spot, where the beam strikes the prism base, the thickness C d7 and the refractive index (η2 ) of the waveguide was measured. Using the developed numerical method in this study, the dispersion characteristics of a three- layer and a four-layer waveguides with n1 = 1, n2 = 1.54, n3 = 1.447 and n1 = 1, n2 = 1. 5, n3 = 1.6 n4 = 1.447. respectively, have been obtained. "

"A study on the design and construction of measurement system of electric current of power line has been carried out. The electromagnetic induction on inductor placed near a power line was used as modulator signal of laser diode. The modulator signal in frequency signal form is obtained by converting the amplitude of induced voltage into frequency signal by voltage-to-frequency converter. The optical light of laser diode modulated by the frequency signal was transmitted by optical fiber. At the output of the fiber, the optical light was detected and converted by optical detector into electrical signal. The electrical signal was then demodulated and amplified by a receiver to be measured by a frequency counter. The experimental result shows a linear property of induced voltage as a function of current in the power line; the frequency as a function of voltage and current is also linear; the frequency on transmitter is the same with the frequency on receiver. It is concluded that the system designed and constructed in this study is applicable for remote measurement of electric current of power line."

"Experimental study on fiber power-splitter using a grating is described. Special attention is paid to the splitting ratio. Experiments were performed with a simple grating confirming the theoretical prediction Double passing of the grating results in a selectable splitting ratio of 5:7. Grating is made by photographic technique. Parameter b (width of slit) and d (period) of grating are designed with computer simulation."