Benzocyclobutene polymer in glass multimode interference thermo-optic switch

Optical switch fabrics are integral parts of optically switched network because these devices are capable to direct input traffic to the appropriate output interface without resorting to optical-to-electrical-to-optical (OEO) conversion. This thesis is significantly devoted towards the design and simulation work of optical switch based on 2×2 multimode interference (MMI) coupler and exploiting thermo-optical properties of materials. Photosensitive BenzoCyclobutene (BCB 4024-40) polymer based coupler material was chosen due to its high thermo-optic coefficient, which offers less power consumption to induce thermo-optic effect in MMI coupler. The switching of the input signal to the desired output ports are realized by modifying refractive index at particular section of MMI coupler. Light propagation and thermal distribution through the optical switch are modeled by using a Finite Difference Beam Propagation Method (FD-BPM). In order to reduce the switching power, further analysis has been done by exploring the effect of heater’s geometrical structure. It was observed that the employment of trapezoidal (tapered) heater structure can reduce the applied switching power by 15.53% as compared to the conventional rectangular structure. This improvement was shown to take place at crosstalk value of -19 dB. Significantly, this research has successfully demonstrated the application of tapered heater electrode in reducing the switching power for thermo-optic switch application

Wide range analysis of ozone gas concentration in ultraviolet region

The purpose of this research is to investigate the development of optical gas sensor employing absorption spectroscopy technique for ozone concentration measurement. Additionally, wide range analysis has been conducted to improve range of ozone concentration measurement using ultraviolet light absorption. Simulation of ozone absorption cross section in ultraviolet region was conducted via Spectralcalc.com® simulator. Simulation result for ozone absorption cross section was then verified by comparison with result from previous studies, showing small percentage of difference less than 3.05 %. In addition, the simulator was also used to investigate the effect of pressure and temperature on ozone absorption cross section. Simulation result showed ozone absorption cross section to exhibit negligible effect of pressure and temperature from 0.1 atm until 2.0 atm and from 293 K until 305 K, respectively. Next, path length of gas cell that suits with detection range of ozone monitor was determined through Spectralcalc.com® simulator. Finally, transmissive type gas cell is fabricated at optimum length of 10 cm. Based on the experiment results wide range analysis was conducted at 10 cm gas cell by consideration of less relative error of concentration. It was observed that wavelengths at 232 nm, 233 nm, 234 nm, 235 nm, 236 nm, 284 nm, 285 nm, 286 nm and 287 nm exhibit capability to measure ozone concentration using ultraviolet light absorption at high concentration value with wide range of concentration measurement from 619 ppm until 932 ppm. Of this, 285 nm was chosen due to its high resolution value at 17 ppm. The sensor exhibits fast response time and recovery time, both at 20 s. Peak of ozone absorption cross sections were observed in both experiment and simulation, located at 260.45 nm and 255.44 nm, respectively. Meanwhile, the values of peak of ozone absorption cross section were observed in experiment and simulation at 164.37 × 10-23 m2 molecule-1 and 114.86 × 10-23 m2 molecule-1, respectively. Significantly, this research has successfully demonstrated possibility of conducting wide-range analysis employing consideration of less relative error concentration. Particularly, vast improvement range of ozone concentration measurement has been achieved by wavelength selection which is far from the peak of ozone absorption cross section

The numerical techniques for thermal distribution analysis in optical waveguides

In this paper, the analysis of thermal distribution in planar optical waveguide cross-section when a single heater electrode applied is presented. Starting from the heat equation, the thermal analysis has been done using two proposed numerical methods which are include finite difference method (FDM) and finite element method (FEM). By considering conduction as the only heat transfer mechanism, the obtained results from the mentioned methods are shown to have a good agreemen

A System of Child Detection in Car Using Thermal Sensor

There are some cases about the child died in the car that causes by the parent did not aware their child being left in the car in long duration time. Therefore, there is a project that can overcome the problem of children being left behind in the car that is a prototype that can detect children in the car by using heat-sensing technology and effective indicators to users so that users are aware of the indicators in the prototype system be created. The system of the prototype consists of Arduino MKR WIFI 1010, thermal sensor, buzzer, LEDs, relay, and power bank that be constructed in circuit. This work evaluates the prototype able to detect child remain in car using thermal sensor with detection range is 37cm on the rear car seat and also able to notify the user about its using indicator LED and buzzer alarm. The prototype will connect to the car to operate as the flow in the flowchart. This prototype helps the user to prevent the child be left in a car

Uric acid detection in visible spectrum

The measurement of uric acid based on the optical absorption at visible light spectrum is investigated and tested. Sensing in the visible region was conducted for determination of suitable wavelength that produces high sensitivity and accuracy performance based on the Beer-Lambert law calculation. In this work, the uric acid is detected by detecting sodium urate as a product of chemical reaction between uric acid with sodium hydroxide buffer. The setup has been tested for uric acid concentration ranging from 15 mg/dL to 85 mg/dL. Three wavelengths have been analyzed which are 460 nm, 525 nm and 630 nm. Measured data at 460nm wavelength exhibits the highest sensitivity, which is 0.0012 (mg/dL)-with 86.51% accuracy. Detection of uric acid at visible light spectrum offers a low-cost sensor based on visible LEDs and photodiode is possible to be realized

Radio Frequency Identification (RFID) based cable detection system

Cable theft issues have been known worldwide in the past years therefore this paper discusses how to overcome them by using radio frequency identification (RFID) technology in which the RFID reader can detect the unique identifier (UID) number of the RFID tag that is attached on the cable. The main objective is to develop the RFID-based cable detection system using both software and hardware. Additionally, this system will analyze how the voltage received by the reader can be affected when the distance between tag and reader is varied. The system is developed by using RFID RC522 and Arduino UNO as the main components. The RFID reader will read the data from the RFID tag and will be sent to the Arduino UNO for processing according to the codes that have been programmed into the Arduino UNO. Once processed, the OLED display will display the RFID tag's unique identifier number along with the location of the cable. The range analysis is done by analyzing the distance between reader and tag and the voltage received by the reader. From the results obtained, the trend of range analysis shows that the nearer the distance, the higher the voltage received by the reader. In summary, the proposed solution to the cable theft issues which is RFID based cable detection system could improve the user’s management by reducing the user’s time to locate the cable. However, the system can be improvised by developing a system with the detection range between reader and tag that can reach up to 1m and above

Investigation of the effect of inlet radius on the response time of a transmission type ozone sensor

The effect of inlet radius of a transmission type optical gas cell on its response time is reported. Six gas cells of varying lengths, and internal radius of 0.32cm were considered at first and then other internal diameters were also investigated afterwards. The effect of inlet radius is easily discernible at all velocities considered; however it is more pronounced at lower flow rates. At a velocity of 16.79cm/s of ozone gas, and for a target sensing time of ≤ 0.5 seconds; we observed that the inlet radius requirements for gas cells of varying lengths and varying internal diameters is not the same for a specific target sensing speed. The length and the internal radius of a gas cell are proportional to its inlet radiu

Wide range analysis of absorption spectroscopy ozone gas sensor

A wide range analysis of spectroscopic ozone gas sensor is conducted in order to obtain specific affected wavelength when 616 ppm to 999 ppm of ozone concentration is released into 5 cm gas cell of transmission type. It is observed that by employing different wavelength in ultraviolet region based on spectroscopic ozone detection, obvious differences of transmittance value are obtained for each particular wavelength. Consideration with Twyman-Lothian equation, specific wavelength at 239 nm, 240 nm, 241 nm, 242 nm, 278 nm, 279 nm, 280 nm, 281 nm is proven to achieve wide range of ozone detection when low relative error of concentration is achieved by value of transmittance in range between 0.25 and 0.5

Unsaturated polyester resin/polymethylmethacrylate waveguide-based refractive index sensor with dual-wavelength temperature compensation

This paper demonstrates an optical waveguide based- refractive index (RI) sensor using the temperature compensation method. The optical waveguide was formed using a polymethylmethacrylate sheet as the cladding material and unsaturated polyester resin as the core material. The sensor design consists of two input waveguide branches, a sensing area and an output branch. Two light emitting diodes with wavelength of 530 nm and 660 nm were used as light sources. In this work, temperature compensation was done by dual-wavelength technique in which RI and temperature sensitivities were measured at two different wavelengths at 530 nm and 660 nm. Based on the RI and temperature sensitivities, temperature compensation was implemented. Experimental fndings indicated that the average relative error of the uncompensated measurement using the light source of 530 nm and 660 nm were 0.4372% and 0.2749%, respectively. Meanwhile, the average error of the temperature compensation method was 0.0344%. Hence, the temperature compensation method provides measurement error up to 92% lower compared to the uncompensated method. As such, the proposed dual-wavelength compensation method could effectively improve the RI measurement accuracy

A review on polymer material for opyical devices application

In this chapter, an overview of polymer material in optical waveguiding technology is presented. This include a review on type of polymer being used worldwide in the development of optical devices, track record and performances of polymer based optical devices and on the external field control of the polymer material for active devices application. Further discussion will then include the current research in polymer based optical waveguiding technology held in our Photonics Technology Centre together with possible development and commercialization