Xiangxin Bi

High-throughput planer glass coating using Laser Reactive Deposition (LRD)

Planar Lightwave Circuit (PLC) technology has been considered as a promising route to integrate a greater number of channels and more optical functionalities onto a small foot print, enabling smaller device sizes and lower costs of manufacturing by using existing semiconductor process technologies. Among several planar technology platforms, silica-on-silicon technology comprised of a silica higher index core and lower index clad has taken the lead in this direction. One of the major advantages of silica based PLC technology is its relative ease to couple to a single mode silica fiber because of a close match of the index and dimensions of the waveguide core of planar chip and fiber. In this structure, to completely confine and guide light signals, the silica layer stack, including lower clad, core and top clad can be as thick as 20 - 40 microns, in which the core layer thickness is around 6 - 8 micron. This has presented a major challenge to several major silica film deposition technologies including CVD, FHD, PVD, and Sol-Gel processes. In addition to basic requirements for optical quality of the glass film, low cost manufacture also demands a high deposition rate to reduce process costs in the fabrication of these planar chips. In this paper, we present a high throughput and planar glass coating technology to lay down doped and undoped glass films at unprecedented rates. The technology is comprised of a laser reactive deposition (LRDTM) process developed based on our nanoscale particle manufacture (NPMTM) methods pioneered by NanoGram Corporation. We report results on planar glass films deposited using this technology and describe the concepts employed using this technology in manufacturing. Furthermore, we will compare it with various existing glass film deposition technologies.

Synthesis of nanoscale optical materials using nanoparticle manufacturing (NPM) technology

Current development of optical network component devices has increased demand for various optical and opto-electronic materials for a wide range of applications such as switches, waveguides, amplifiers, Bragg gratings, splitters, isolators circulators, lasers and detectors. Furthermore, low cost manufacture of component devices demands higher and higher integration of individual components onto a small, planar foot print. One of the major issues with optical integration is that various optical functionalities come from materials with different compositions. As a result, it is highly desirable to have a means to produce high quality optical materials with various compositions, and to deposit them onto a common substrate. We present in this paper a novel nanoscale materials synthesis method to produce optical materials in nanoscale particulate form, which can subsequently deposited onto a substrate at a high deposition rate. Further treatment of these materials on the substrate can be used to transform these nanoscale particle building block into dense solids to achieve optical functional properties such as optical transparency, amplification or UV sensitivity.

Laser reactive deposition (LRD) processing for planar lightwave circuit (PLC) manufacturing

This report will present a new and highly versatile manufacturing technology, Laser Reactive Deposition (LRDTM) processing, to produce planar glass coatings for planar lightwave circuit (PLC) manufacturing. Planar glasses with a wide range of glass compositions offering various passive and active optical functionalities have been produced using this technology. In particular, LRDTM processing removes a major bottleneck experienced by existing glass fabrication technologies in the high speed deposition of thick and complex glasses. In LRDTM processing, instead of depositing atoms or molecules a layer at a time, nanoscale particles produced in situ are used as fundamental building blocks for planar glass fabrication. The significantly larger mass of these nanoscale clusters in comparison to atoms or molecules has enabled a much higher throughput and lower cost. Optical quality glasses are obtained by a subsequent high temperature consolidation process. The nanoscale particle size and narrow size distribution, uniquely offered by LRDTM processing, are critical for the fabrication of high optical quality planar glass. We have demonstrated in this work that LRDTM processing can produce high quality doped waveguide glasses such as phosphorous-doped silicate glass and UV photosensitive glasses such as germanium-doped silicate glass. We have also demonstrated the capabilities of LRDTM processing in controlling refractive index and layer thickness of the waveguide core to achieve single mode light propagation at 1.55 microns. Finally, we will present characterization results on basic parameters including propagation loss, surface roughness, and refractive index and thickness uniformity on 4 inch planar glass wafers deposited using LRDTM processing.