In addition corner analysis of varying widths and heights of the waveguide was also performed. For height, we varied the value between 215.3nm and 223.1nm. For Width, we varied the value between 470nm and 510nm. We found that at 510 by 215 we had the lowest group index of roughly 4.17 and at 470nm by 223nm we had a group index of roughly 4.25. Performing a series of calculations to find the FSR for a variety of length changes and group indices we found the following: