"Silicon Photonics Design – From Devices to Systems", by Lukas Chrostowski and Michael Hochberg, Cambridge Press 2015, https://doi.org/10.1017/CBO9781316084168
The book is available for purchase as an EBook or Hardback from Cambridge (see also Amazon, etc.). Some universities/institutions have a subscription to this book, offering free PDF downloads. If you don't have it, you can click on "Recommend to a Librarian", or speak with your librarian to request it.
The book includes example scripts (Lumerical Solutions, Matlab, Mentor Graphics), which are hosted on this repository.
Download a ZIP file of this repository: https://github.com/lukasc-ubc/SiliconPhotonicsDesign/archive/master.zip
Eq. (4.53) should be the average of the effective index values, rather than their difference.
Eq. (4.10c) should be equal to π/2, and Eq. (4.12b) should be equal to i|kappa|^2 (the negative sign should be removed).