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"In this research work an experiment on the application of fiber sensor for measuring an acoustic vibration has been carried out. A light beam from He-Ne laser source was into two arms of Mach tender Interferometer. Each arm of the interferometer was a piece of optical fiber with a length of 2 m.The beam transmitting through the sensing arm was modulated in phase by an acoustic vibration produced by a signal generator. The output of this fiber was interfered with the light radiated from the undisturbed fiber, the reference arm of the interferometer. A fringe counter measured a fringe shift due to the vibration of the acoustic signal. The measurement shows a good response in terms of the number of fringes with respects to the acoustic vibration in a frequency range of 10 Hz up to 40 Hz. It is concluded that the system is applicable to measure an acoustic vibration with an accuracy of 7 %."

"An optical fiber sensor for measurement of liquid parameters, such as refractive index and concentration has been developed. The measurement method is based on the attenuation of cladding mode power. A normal core-clad fiber with a leaky ray zone is used as a sensor. A portion of the clad power is measured by means of a tapered fiber whose diameter d is so chosen that it is always less than or equal to the thickness of the clad. The maximum clad power is detected when the diameter of the probe is nearly equal to the clad thickness."

"[Pada umumnya sensor Fiber Bragg Grating (FBG) bekerja berdasarkan pengamatan karakteristik respon spektral FBG terhadap besaran yang ingin dideteksi. Pada tesis ini dipelajari kemungkinan pemanfaatan respon intensitas FBG untuk mengamati besaran yang ingin dideteksi, khususnya regangan statis dan dinamis. Hasil pengujian menunjukkan bahwa intensitas transmisi dan refleksi FBG berbanding lurus dengan regangan statis dan dinamis. Berdasarkan karakteristik FBG tersebut, dilakukan rancang bangun sensor getaran FBG untuk mendeteksi getaran pada frekuensi rendah. Sensor ini dibuat dengan cara menempelkan sebuah FBG pada kantilever berbahan perunggu dengan dimensi 85x3x0,5 mm. Hasil pengukuran pada rentang temperatur 25 ? 450C menunjukkan bahwa sensor ini dapat mendeteksi getarandalam rentang frekuensi 7?10 Hz. Rentang frekuensi ini termasuk dalam rentang frekuensi aktivitas penggalian, sehingga dapat diterapkan pada sistem deteksi tindakan vandalisme pada jalur pipa minyak.;In general, Fiber Bragg Grating (FBG) sensor works based on the observation of spectral response characteristic to detect the desired parameter. In this thesis, we studied the possibility of using the FBG intensity response characteristic to detect the desired parameter,especially in static and dynamic strain. Experiment result show that the transmitted and reflected intensity have linier relationships with static and dynamic strain. Based on these characteristics, we developed the FBG sensor to detect low frequency vibration. This sensor is designed by attaching the FBG on the bronze cantilever with dimensions of 85x3x0.5 mm. Measurement results show that the sensor is able to detect vibrations in the frequency range of 7-10 Hz at a temperature range of 25-450C. The measured frequency range is still within thefrequency range of digging activity, therefore this vibration sensor can be applied on oil pipelines vandalisation detection system.;In general, Fiber Bragg Grating (FBG) sensor works based on the observation ofspectral response characteristic to detect the desired parameter. In this thesis, we studied thepossibility of using the FBG intensity response characteristic to detect the desired parameter,especially in static and dynamic strain. Experiment result show that the transmitted andreflected intensity have linier relationships with static and dynamic strain. Based on thesecharacteristics, we developed the FBG sensor to detect low frequency vibration. This sensor isdesigned by attaching the FBG on the bronze cantilever with dimensions of 85x3x0.5 mm.Measurement results show that the sensor is able to detect vibrations in the frequency range of7-10 Hz at a temperature range of 25-450C. The measured frequency range is still within thefrequency range of digging activity, therefore this vibration sensor can be applied on oilpipelines vandalisation detection system., In general, Fiber Bragg Grating (FBG) sensor works based on the observation ofspectral response characteristic to detect the desired parameter. In this thesis, we studied thepossibility of using the FBG intensity response characteristic to detect the desired parameter,especially in static and dynamic strain. Experiment result show that the transmitted andreflected intensity have linier relationships with static and dynamic strain. Based on thesecharacteristics, we developed the FBG sensor to detect low frequency vibration. This sensor isdesigned by attaching the FBG on the bronze cantilever with dimensions of 85x3x0.5 mm.Measurement results show that the sensor is able to detect vibrations in the frequency range of7-10 Hz at a temperature range of 25-450C. The measured frequency range is still within thefrequency range of digging activity, therefore this vibration sensor can be applied on oilpipelines vandalisation detection system.]"

"ABSTRACT As transmission medium in optical communication system, optical fiber is also characterized by elastic properties beside of transmission properties of optical fiber. The Young Modulus of Elasticity of optical fiber could be measured by considering a bare optical fiber as cantilever which resonant with an acoustical vibration. To detect the cantilever vibration, a HeNe laser light is launched into the cantilever of optical fiber through its free end and the output laser light is detected by a PMT and observed by the channel 2 of an oscilloscope. Channel 1 of the oscilloscope observes the signal of the acoustical vibration. Regulating both the frequency and amplitude of the vibration or the position of the pinhole of the PMT, the resonance frequency of the cantilever could be detected accurately. Using the data of the resonance frequencies of various length of the cantilever has been calculated. "

"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."

"Fiber Optic Ring Resonator dapat digunakan sebagai sebuah sensor optik. Hal tersebut dilakukan dengan memanipulasi variabel – variabel yang mempengaruhi output persamaannya, yaitu panjang fiber L, intensitas rugi fraksional coupler γ!, koefisien coupling κ dan atenuasi amplitudo fiber α!. Variabel – variabel tersebut mempengaruhi parameter output berupa: FSR (Free Spectrum Range), FWHM (Full Width Half Maximum) dan F (Finesse). Dengan memanipulasi parameter output dari FORR, maka pengguna dapat menggunakannya sesuai kebutuhan sensor optik yang dibutuhkan.

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One of the most common application of Fiber Optic Ring Resonator is as an optical sensor. Manipulating variables in the equation to measure the energy from the FORR, which are fiber’s length L, fractional loss coupler intensity γ! , coupling coefficient κ and fiber’s amplitude attenuation α!, which affect its output parameters. Those output parameters are Free Spectrum Range FSR, Full Width Half Maximum FWHM and Finesse F. By manipulating the output parameters manipulated, the users will be able to apply as an optical sensors based on their own requirements."