Mohd Kamil Abd Rahman

Low Cost 1 £ 2 Acrylic-based Plastic Optical Fiber Coupler with Hollow Taper Waveguide

A 1 £ 2 Plastic optical flber (POF) Y-coupler has been designed and fabricated using a simple acrylic (PMMA) mold insert. The device is composed of three segments: an input POF flber, an intermediate hollow taper waveguide and output POF flbers. The acrylic mold insert has been fabricated using EGX-400 desktop engraver machine with a spindle speed of 15Krpm and feed rate of 5mm/sec. The engraved regions which is a form of U-groove allows 1mm core step index PMMA POF flbers to be slotted into the mold insert. The short POF flbers at the input and output ends are slotted inside the mold insert before the interfaces of the taper waveguide. A top acrylic plate is then placed on top of the fabricated device and sealed. The flnal device has been tested for both splitter and combiner operations for an efiective power of 1mW. The device has an insertion loss of 10.48dB. In the splitter operation, the device has a splitting ratio of 52:48. In the combiner operation, the combined power is i11:15dB for input power of i11:90dB and i12:05dB.

Design and fabrication of an acrylic-based 1×2 POF coupler using CNC Machining

A low cost acrylic-based 1times2 Plastic optical fiber (POF) coupler has been designed and fabricated. The POF coupler has a middle waveguide taper made of UV curable glue and POF fibers for the input and output ports. Non-sequential ray tracing has been performed on the POF coupler. Mold insert has been fabricated using EGX-400 desktop CNC machining with a groove opening of 1 mm which allows the 1 mm core size POF to be slotted into the mold insert. Norland NOA-71 UV curable glue is injected into the waveguide taper region and cured using UV exposure source. The device has an insertion loss of 8 dB and excess loss of about 4.6 dB.

Hollow optical waveguide coupler for portable access card system application

A new application of an asymmetric hollow optical waveguide coupler is presented. The asymmetrically-design hollow waveguide coupler provides a unique series of output power which successively is used as an optical code in a portable access card system. The output power are arranged in a way that it will represent a unique optical code. The waveguide design combines two major structures which are asymmetric Y-junction splitter and linear taper. The use of a basic lx2 asymmetric waveguide coupler design together with a cascaded design technique allow more complex and higher level hollow waveguide coupler to be constructed. The code combination generated by the waveguide coupler theoretically provides the access card system with millions of possible code combination as the number of output ports increases. The code combination of the waveguide coupler is derived using combinatory number theory where the combination is dependable on the number of output ports.

Acrylic-based Y-branch plastic optical fiber attenuator

A low cost acrylic-based Y-branch plastic optical fiber (POF) attenuator has been developed. The device is based on a simple Y-branch structure and composed of three segments: an input POF waveguide, a middle variable hollow waveguide taper and output POF waveguides. Non-sequential ray tracing model has been performed on the device showing the device working as simple two-port attenuator. The device mold insert has been fabricated using a desktop engraver machine with a U-groove opening of 1 mm which allows 1 mm core size POF fibers to be slotted into the mold insert. The attenuation of the device can be adjusted by a simple waveguide taper spacing controlled by the spacing of the input POF fiber in the hollow region. The device has a channel uniformity of 0.3 dB, coupling ratio of 53∶47 and excess loss of 3.7 dB. Device attenuation ranges from 6.9 dB to 9.4 dB has been obtained for a waveguide taper spacing of 0 to 6 mm.

Embedded FBG Sensor in Aircraft Smart Composite Materials for Structural Monitoring

This paper describes the use of embedded Fiber Brag Grating (FBG) sensor in the honeycomb core carbon fiber sandwich panel in smart composite materials for the application of monitoring the structural integrity of an aircraft. A part of vertical stabilizer was selected and reproduced using carbon fiber honeycomb core sandwich panels. The sandwich panel was fabricated in accordance to the generic sandwich structure and aviation industry standards, including the materials and also the method of construction. Using a carbon fiber from Hexcel as the face-sheet, Nomex honeycomb as the core, the sandwich panel was cured using Hysol EA9330 resin according to a standard curing process in the aviation industry. In order to make the sandwich panel as smart materials, optical sensor which has fiber bragg grating arrays, FBG, were embedded between the carbon fiber plies during the lay-out process. Using an FBG data logger and Instron 8802 Universal Testing Machine, the panel was subjected to flexural load and the FBG sensor signals were read at the load interval of 0.2 kN. From the experiment the results were taken and data was plotted and it shows that the FBG signals responded well to the load applied. In the future, the specimen will be used for further experiment for measuring strains and establishing the existence of damage in the panel.

Acrylic-based 1×2 Y-Branch POF coupler with high index contrast waveguide taper

An acrylic-based 1×2 Y-Branch POF coupler consist of input POF waveguide, a middle high index contrast waveguide taper and output POF waveguides has been developed and modeled using non-sequential ray tracing. The waveguide taper provide an all passive alignment with insertion loss of 4.68 dB and coupling ratio of 50∶50.

Performance of newly-fabricated modular surface plasmon resonance (mSPR) sensor

Performance of modular surface plasmon resonance (mSPR) sensor based on refractive index is discussed in this paper. The sensor was built in house using a polychromatic light source, polarizer to produce a transverse magnetic wave, high refractive index waveguide, gold-coated disk, single channel cell and spectrometer for data analysis. A knob for adjusting the angle of the incident provides a means for ease of angle variation which simplifies the design of the instrument for portability purposes. In conventional SPR, the light source need to be delocalized for search of the resonance angle, making the instrument bulky in size and had to be laboratory-based. The efficiency of the newly designed SPR biosensor was tested using a various percentages of ethanol in deionized water. Observations on the shifts of the resonance wavelength with ethanol strength revealed that the SPR biosensor has a sensitivity of 64 nm/RIU and a resolution of ~102 RIU.

Metal-Based Asymmetric Hollow Waveguide and Y-Branch Plastic Optical Fiber Couplers

Metal-based asymmetric plastic optical fiber couplers based on hollow waveguide and Y-Branch structures have been developed. Non-symmetrical coupling ratios were obtained by controlling the tap line width of the metal hollow waveguide whereas a simple attenuation technique based on lateral displacement of two fibers is used for the Y-branch. The asymmetric hollow waveguide coupler fabricated on metallic block shows a tap-off ratio or TOFR variation of 10.7% to 89.3%, for a tap width of 500 um to 1 mm. The asymmetric Y-branch design provide a range of coupling ratios from 14.23% to 85.77% for an output fiber lateral displacement of 0.1 mm to 4.4 mm. The excess loss of these devices varies from 9.49 dB to 11.51 dB for the asymmetric hollow coupler and 6.3 dB to 8.3 dB for the Y-branch coupler.

Acrylic-Based 1x2 Plastic Optical Fiber Coupler Device Manufacturing Using EGX400 Desktop Engraver System

An all-acrylic-based 1x2 plastic optical fiber (POF) coupler has been designed and manufactured. The optical device is based on a simple 1x2 Y-branch coupler design with a middle high index contrast waveguide taper and splitting ratio of 50:50. Device modeling has been performed using non-sequential ray tracing with an insertion loss of 4.68 dB. Machining of the optical device has been performed using EGX400 desktop engraver system. 1 mm milling tool size with machine spindle speed of 15,000 rpm has been utilized. A simple optimization on the milling process prior to machining improved the coupling surfaces between the POF fibers and the waveguide taper. POF fibers are inserted into the engraved u-grooves and are passively aligned to the waveguide taper. The measured insertion loss is 7.5 dB and with a splitting ratio of 50:50.

Preliminary research in characterization of fatigue load parameters using fiber optic

Fatigue is the primary cause of structural failure. Fatigue failures are caused by fatigue loadings in the form of cyclic loads. To avoid fatigue failures, structures need monitoring. This paper reports a study of optical fiber Bragg grating responses under variable amplitude fatigue load.Use of optical fiber in monitoring structural condition becomes extensive research nowadays due to its advantageous characteristics than conventional method such as using strain gauges. A standard specimen (ASTM E606) will be used for initial study and followed by implementing the concept to the wing-box structure. The specimens will be attached with fiber Bragg grating sensor and test configuration will be set up. All the data and information will be analyzed then a comparison with strain gauge sensor will be done for validation.