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80
Figure 4.2: Bandstructure for W1, Type-A PCWG with SiO2 bottom
cladding for core index of 3.4 and r/a of 0.3. (Courtesy of Adam Mock)
The propagation loss for this structure is shown in Figure 4.3(b). As expected from the
bandstructure, this structure suffers from very high losses - greater than 200cm-1 on
average - over all but a tiny sliver of the transmission band. The minimum loss is almost
zero but exists over a bandwidth of only 4nm and occurs at a slightly lower frequency
than the loss maximum, which is almost 1000cm-1.
The group index as a function of frequency for the W1, Type-A PCWG with 2Im SiO2
bottom cladding closely resembles the group index for the undercut structure and is
plotted in Figure 4.3(a). The primary difference between the undercut and on-oxide
structures is that the higher index of the SiO2 reduces the slope of the light line, leaving
only a small range of β-values for which the guided mode is outside the light cone.
Incidentally, this range of β-values below the light cone is also the range of β-values over
Object Description
| Title | Silicon-based photonic crystal waveguides and couplers |
| Author | Farrell, Stephen G. |
| Author email | stephenf@usc.edu; sgfarrell@yahoo.com |
| Degree | Doctor of Philosophy |
| Document type | Dissertation |
| Degree program | Electrical Engineering |
| School | Viterbi School of Engineering |
| Date defended/completed | 2008-09-05 |
| Date submitted | 2008 |
| Restricted until | Unrestricted |
| Date published | 2008-10-20 |
| Advisor (committee chair) | O'Brien, John D. |
| Advisor (committee member) |
Dapkus, P. Daniel Steier, William Haas H., Stephan |
| Abstract | Most commercial photonics-related research and development efforts currently fall into one or both of the following technological sectors: silicon photonics and photonic integrated circuits. Silicon photonics [18] is the field concerned with assimilating photonic elements into the well-established CMOS VLSI architecture and IC manufacturing. The convergence of these technologies would be mutually advantageous: photonic devices could increase bus speeds and greatly improve chip-to-chip and board-to-board data rates, whereas photonics, as a field, would benefit from mature silicon manufacturing and economies of scale. On the other hand, those in the photonic integrated circuit sector seek to continue the miniaturization of photonic devices in an effort to obtain an appreciable share of the great windfall of profits that occur when manufacturing, packaging, and testing costs are substantially reduced by shrinking photonic elements to chip-scale dimensions. Integrated photonics companies may [12] or may not [34] incorporate silicon as the platform.; In this thesis, we seek to further develop a technology that has the potential to facilitate the forging of silicon photonics and photonic integrated circuits: photonic crystals on silicon-on-insulator substrates. We will first present a brief overview of photonic crystals and their physical properties. We will then detail a finely-tuned procedure for fabricating two-dimensional photonic crystal in the silicon-on-insulator material system. We will then examine transmission properties of our fabricated devices including propagation loss, group index dispersion, and coupling efficiency of directional couplers. Finally, we will present a description of a system for adiabatically tapering optical fibers and the results of using tapered fibers for efficiently coupling light into photonic crystal devices. |
| Keyword | photonics; photonic crystal; silicon; integrated photonics; SOI; optoelectronics; waveguides; couplers; optical fiber; tapered fiber; evanescent coupling; adiabaticity; silicon photonics |
| Language | English |
| Part of collection | University of Southern California dissertations and theses |
| Publisher (of the original version) | University of Southern California |
| Place of publication (of the original version) | Los Angeles, California |
| Publisher (of the digital version) | University of Southern California. Libraries |
| Provenance | Electronically uploaded by the author |
| Type | texts |
| Legacy record ID | usctheses-m1681 |
| Contributing entity | University of Southern California |
| Rights | Farrell, Stephen G. |
| Repository name | Libraries, University of Southern California |
| Repository address | Los Angeles, California |
| Repository email | cisadmin@lib.usc.edu |
| Filename | etd-Farrell-2433 |
| Archival file | uscthesesreloadpub_Volume32/etd-Farrell-2433.pdf |
Description
| Title | Page 91 |
| Contributing entity | University of Southern California |
| Repository email | cisadmin@lib.usc.edu |
| Full text | 80 Figure 4.2: Bandstructure for W1, Type-A PCWG with SiO2 bottom cladding for core index of 3.4 and r/a of 0.3. (Courtesy of Adam Mock) The propagation loss for this structure is shown in Figure 4.3(b). As expected from the bandstructure, this structure suffers from very high losses - greater than 200cm-1 on average - over all but a tiny sliver of the transmission band. The minimum loss is almost zero but exists over a bandwidth of only 4nm and occurs at a slightly lower frequency than the loss maximum, which is almost 1000cm-1. The group index as a function of frequency for the W1, Type-A PCWG with 2Im SiO2 bottom cladding closely resembles the group index for the undercut structure and is plotted in Figure 4.3(a). The primary difference between the undercut and on-oxide structures is that the higher index of the SiO2 reduces the slope of the light line, leaving only a small range of β-values for which the guided mode is outside the light cone. Incidentally, this range of β-values below the light cone is also the range of β-values over |
