Tuesday, October 1, 2019

Essay --

In this paper straight line structures are generated on surface of Polymethylmethacrylat (PMMA) with UV-Lamp and Excimer-Laser in order to photolytically increase its refractive index to allow guiding of light in the sample. The structures were engraved using contact mask sampling on surface of PMMA with UV-Lamp (spectrum wavelength 100nm - 410nm) and Excimer-Laser (wavelength 248nm) supplemented by micromachining directly on surface of PMMA with Excimer-Laser. The fabricated structures on the surface of PMMA of few micrometers were then examined for its change in refractive index using a single mode ber (wavelength 670nm) and Beamlux II softwarea. Our sim- ple experiment compliments the previously found studies such that refractive index pro le strongly depends on the irradiation doses, uence and laser pulse rate. The conclusion points toward using PMMA substrate for optoelectronic use by creating waveguides with UV or Excimer-laser because it is an inexpensive, simple and fast method. Masks allow creating waveguides with single mode property with width as small as 3um allowing speci c-to-need created structures and waveguides by altering irradiation parameters. It is wise to point out that the experiment has been thoroughly researched however conducted in a narrow scope of a laboratory project complimenting the lectures for understanding the electromagnetic theory of wave guide and ray optical mode of propagation in planar subwave but only with the aim of creating a substantial understanding of working principles behind waveguides only to serve later for as a ground work for thesis, new ndings or research purposes. Indeed polymers have become very important in the eld of integrated optics area for communication and sensor t... ...ntrast between fabrication of UV lamp and Excimer laser. Since we did not use the detector, it can be the UV Lamp power rating had degraded over the passage of time. Waveguide ends on the mask were not polished either before being irradiated. The PMMA sample was manufactured by Roehm GmbH which includes UV stabilizing characteristic 6. Furthermore, Frank[21] has been able to produce excellent waveguides with UV radiation but with uence at 1mW=cm2 and irradiated for 2-3 hours totaling a complete dose in the range of 7J=cm2 to 14J=cm2 . Therefore, we concluded that perhaps our irradiation and complete dose was too little to cause a refractive index change. The whole experiment was conducted over a period of approximately 10 weeks and no change in the waveguides over the passage of time was observed which points towards its practical application in sensor technology.

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