Photograph of an <a href="https://en.wikipedia.org/wiki/FC_connector" class="extiw" title="w:FC connector">FC</a>-connected optical fiber coupler with adjustable fiber-to-freespace coupling lens. The whole fiber coupler is mounted on a tunable mirror mount.
<a href="//commons.wikimedia.org/wiki/User:Geek3" title="User:Geek3">Geek3</a>
CC BY-SA 4.0
<span class="int-own-work" lang="en">Own work</span>