Polymer Integrated Optics: Device Architectures and Fabrication Methods

Citation

Paloczi, George T. (2005) Polymer Integrated Optics: Device Architectures and Fabrication Methods. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/W41G-2374. https://resolver.caltech.edu/CaltechETD:etd-05102005-112605

Abstract

Polymer materials are becoming increasingly important for integrated photonic circuits in optical communications networks. The optical and mechanical properties of polymers for integrated optics are explored in this thesis and it is shown that the manipulation of these properties leads to developments that in other optical materials could not be achieved as quickly or as easily, or not achieved at all.

So that the benefits of a large range of operating wavelengths due to low material dispersion in polymers, are not lost to the wavelength dependence of optical couplers, we design wavelength-invariant couplers using a geometrical representation of coupled mode theory. Simulations of the resulting couplers confirm a virtually constant response over a large range of input wavelengths.

The direct-write ability of electron beam sensitive polymers enables rapid fabrication of high-precision optical devices. Microring resonator optical filters and a compact microring-based inline reflector are fabricated by this method and characterized. Chaining multiple rings together results in the coupled resonator optical waveguide (CROW). A CROW-Mach-Zehnder interferometer is fabricated and the measured response corresponds well with the predictions based on the matrix theory.

Polymer materials can be patterned by a variety of methods not possible with traditional optical materials. Soft-stamp replica molding presents a means to further reduce the costs of implementing polymer materials. Demonstrating the potential of the method, microring resonators are fabricated, with excellent agreement between the responses of the original and the replica. To further demonstrate the effectiveness of the process, it is applied in the fabrication of Mach-Zehnder modulators. The modulators exhibit excellent properties, with single-arm modulation voltages of 8 V and extinction ratios better than 19 dB. Successive repetition of the molding process allows for multilayer polymer optical devices. Finally, the flexible properties of polymers are exploited for pliable, all-polymer freestanding optical circuits.

Thesis Files