Laser direct write optical waveguides for optical interconnection and optical isolation

Date of Award




Degree Name

Doctor of Philosophy (Ph.D.)


Electrical and Computer Engineering

First Committee Member

Michael R. Wang - Committee Chair


Optical channel waveguides are essential in integrated optics and lightwave technology. Low optical waveguide propagation loss, ease in waveguide fabrication, flexible waveguide patterning, and excellent waveguide stability have been important goals of recent research and development. One of the focuses of this dissertation is the demonstration of maskless non-lithographic fabrication of low-loss optical waveguides on high-energy-beam sensitive glass and on new laser writable photopolymer materials. The demonstrated fabrication techniques offer fast waveguide device prototyping, high waveguide production yield rate, and flexibility in waveguide pattern modification.Both the waveguide material properties and the waveguide device parameters have been examined in detail. The index of refraction and propagation loss of the waveguides at the communication wavelength of 1550 nm have been experimentally measured. The fabricated waveguides were found to be low loss, from -0.25 to -0.67 dB cm 1, single mode at 1550 nm wavelength, and stable for a long period of time (more than 5 months of observation).Because of the significant developments on the low loss waveguide fabrication, its potential application to the optical interconnection on the electronic circuit board has been examined. A laser writable polymer waveguide is used to interconnect a laser transmitter array and a photodetector receiver array. The laser direct writing of channel waveguides completes the optical interconnect lines from the laser array to the photodetector array. The laser writing is a flexible packaging process with its flexibility comparable to the electronic wire bonding used extensively in the electronic packaging industry. Also, the laser writing has been used to realize optical waveguide fan-out devices with real-time repair features not available by other fabrication processes.Besides the material and fabrication technology development, this dissertation research has also addressed a novel device design and its realization. Optical isolators are required device components for the optical fiber communication applications to reduce optical return beams to the laser transmitters since the return beams to the laser cavities can result in laser stability problems. Conventionally, the optical isolators are fabricated by using a Faraday polarization rotator with an external permanent magnet. Although such optical isolators have demonstrated excellent performance and low cost commercial devices are available, the optical isolators are not capable of packaging with high-density laser array chips. (Abstract shortened by UMI.)


Engineering, Electronics and Electrical

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