Light travels fast, but in many applications, even a small mismatch in timing can ruin results. For example:​ In laser research, you might need two light beams to hit a sample at almost the exact same moment—an optical delay line lets you tweak one beam’s path to match the other.​ In optical communication systems, delayed signals can cause data errors; delay lines help align signals so information transfers smoothly.​ In industrial laser processing (like cutting or engraving), precise light timing ensures consistent results, avoiding uneven cuts or material damage. link: https://www.cq-smart.com/optical-delay-line