After the test of Mach-Zehnder, we need to install it in reality. But we change the original design. Thanks to the optocad code of tomuta-san, I revise it and do the simulation.

We have considerations:

1. The stable lock of filter cavity. We decided to use MZ only for the Mode cleaner and OPO. 

2. The focal length of lense is limited. So I asked yuefan to give me the list of lense we have. I select focal length of 50mm and 75mm. 

3. We need to adjust the position of these two lenses to have a good mode matching.

The change can be seen in the attached picture 1. We will start to install it tomorrow.