fiber coupled Electro Optics

Mode Matching Telescope

The installation of a new mode matching telescope (MMT) has been performed in order to inject a right beam mode into the main interferometer. This change is due to the change of the recycling cavity length. The MMT was installed after the MC and the Faraday Isolator inside of the vacuum chambers. And the MMT consists of two curved mirrors; a concave mirror and a convex mirror. This page explains how it was designed and installed.

Here is the plot with the ideal mode of the mode cleaner shown in brown. The ideal mode was plotted with the radius of curvature of 18.4. The blue curve is the fit to the vertical beam radius, the purple curve is the fit to the horizontal beam radius, * denotes a data point from the vertical data, and + denotes a data point from the horizontal data.

waist for vertical mode [mm]	w0_v	1.59 ± 0.01
waist for horizontal mode [mm]	w0_h	1.51 ± 0.01
waist position for vertical mode [mm]	z_v	673 ± 28
waist position for horizontal mode [mm]	z_h	1 ± 29

waist for vertical mode [mm]	w0_v	2.81183 +/- 7.793e-03
waist for horizontal mode [mm]	w0_h	2.9089 +/- 1.998e-02
waist position for vertical mode [m]	z_v	5.35487 +/- 0.2244
waist position for horizontal mode [m]	z_h	1.95931 +/- 0.4151

All the distances are calibrated from the position of MMT2 i.e. the position of MMT2 is set to be zero.

The scripts here find the optimal Mode Matching options for the upgraded 40m Mode Matching Telescope.The scripts are in the 40m SVN:
/trunk/docs/jenne/ModeMatchingTelescope/
The main script is MMTmodematching.m It utilizes many of the other scripts in the folder.
The MMT is now finalized, and Koji is going to finish placing the MM optics on the table layout according to these numbers. A summary has been written up and put in the same SVN folder, and is linked here: MMT Summary. Table 2 from the document lists the final distances between each optic: