Merging light beams from the 4 VLT telescopes

ESPRESSO is a fiber feed ultrastable High Resolution Spectrograph designed to work in the Combined-Coude focus of Very Large Telescopes (VLT). A high resolution (R~100000) and an ultra-high resolution (R~220000) mode will be available to collect the light coming of one VLT telescope. In addition, ESPRESSO has an observing mode which allows to collect light of 2, 3 or 4 VLT units. This mode can feed simultaneously the spectrograph using a 4x1 fiber combiner. In the combiner, the light from 4 octagonal fibers will be mixed when projected onto a square fiber, as a double scrambler device. Here it is presented the design, manufacture, integration and tests for the 4x1 combiner of the ESPRESSO Fiber Link.