Fiber-based Near-Infrared Heterodyne Interferometer

This is the setup for the initial static ground tests, and quasi-static sky tests (north-south direction at highest elevation). For the east-west sky experiment the fringing has to be stopped. For this, a fiber-frequency shifter is inserted between the 50/50 splitters at each of the telescopes. The one is tuned for 50MHz, the other for 50 MHz+b*47Hz/m (b is the projected baseline length).