We present the results on fabrication of plastic integrated optical elements using molding, liquid jet delineation, and UV irradiation. Coupling gratings with a period of 620 mm-1 and a diffraction efficiency of 3.3 percent were molded in a preheated poly(methyl methacrylate) planar waveguide using master saw shaped grating. An experimental device is also described which uses computer controlled micro syringe to dispense polymer solution onto a moving substrate. This device consumes thousand times less material to produce integrated optical circuits than equivalent spin- casting equipment.We have made various structures such as Y- branches and Mach-Zehnder interferometers. All the structures demonstrated good performance. The same device was also equipped with a microscope-type UV illuminator for noncontact delineation of optical structures in polyimide films. The operation is based on the refractive index increase due to photo-oxidative decomposition of the material. The index difference 0.02 between exposed and unexposed regions is sufficient to define light guiding channels in polyimide without using liquid developing. UV radiation was also used to make graded-index polyimide waveguides. Their refractive index profile was successfully reconstructed by a specially developed calculation technique. All the techniques combined together give us the cost efficient tool for the fabrication of plastic integrated optics.
We present the results of study of thin film optical waveguides based on photocrosslinkable polyimide with glass transition temperature approaching 400 degrees C. The birefringence of the waveguides can possibly be reduced by eliminating the effect of gravity on the conditions of the film fabrication. We propose fabrication technique that allows us to change the orientation of the substrate and to analyze the gravity effect on the polyimide waveguide. This technique uses UV assisted film deposition from polyimide solution on a transparent substrate mounted as a removable wall of the container with the solution. The technique is also suitable for film fabrication at low gravity conditions. In order to investigate possible effects that can occur during UV assisted liquid deposition at low gravity, we studied UV exposed polyimide films made by spin coating at normal conditions. We describe the appearance of a gradient index waveguide on the top of polyimide coat exposed to UV light. The proposed mechanism of the waveguide formation includes photocrosslinking followed by UV assisted modification of the material which leads to the increase of the optical absorbance in UV region accompanied by the refractive index increase in visible region. Theoretical model based on this approach allowed us to reconstruct the refractive index profile n the waveguide. The profile is in good agreement with that obtained from the waveguide mode spectrum measured with prism coupling technique.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.