Optical Layout

Conceptual design


Usually, optical layout of an IFO is designed using a generic CAD (such as AutoCAD) or a special optical CAD (e.g. Zemax). We haven't used Zemax so I have no word on it.

Using a generic CAD was the original plan for LCGT optical layout. However, as I work on it, several problems were identified.

Therefore I (Y. Aso) wrote a small python library to programatically create optical layouts. The library is called gtrace (meaning Gaussian ray-Tracing), and easy to use. The library features:

By using the library, one can turn logical requirements such as the RC optical lengths, folding angle, ITM surface normal directions (they have to be orthogonal), etc into a real optical layout in a systematic way by writing a program. Once the program is written, it is easy to change wedge angle or substrate material, because all you have to do is to re-run the program to generate a new optical layout.

An example of LCGT layout (by no means the final version) is attached: LCGT_Sample_OptLayput.pdf.

A python program used to generate the layout is also attached: OptLayout.zip.

Software requirements for using gtrace

gtrace requires the following Python modules/packages be installed in your system. For Windows users, it is easiest to install pythonxy (http://www.pythonxy.com/) as their contains all the necessary libraries. For Mac users, the 32bit version of Enthought Python Distribution (EPD) is free of charge for academic use (http://www.enthought.com/products/edudownload.php). Windows and Linux versions are also available. Most Linux distributions have the necessary libraries in their package system.

You also have to set the environmental variable PYTHONPATH to point to the OptLayout directory, which you get when you extract the zip file.

See here for more information on setting up scientific computing environment with Python.

LCGT/subgroup/ifo/ISC/OptLayout (last edited 2010-08-20 12:20:49 by DaisukeTatsumi)