Optical engineering is the field of study which focuses on applications of optics.
Optical engineers design optical instruments such as microscopes, telescope and other equipment that utilises the properties of light, including optical sensors and measurement systems, as well as lasers, fiber optics communication systems, optical disc systems (e.g., CD,DVD),and many others.
Since optical engineers want to design and build devices that make light do something useful, they must understand and apply the science of optics in substantial detail, in order to know what is physically possible to achieve. But they also must know what is practical in terms of available technology, materials, costs, design methods, etc. As with other fields of engineering, computers are important to many (perhaps most) optical engineers. They are used with instruments, for simulation, in design, and for many other applications. Engineers often use general computer tools such as spreadsheets and programming languages, and they also make frequent use of specialized software designed specifically for their field.
Optical engineering metrology uses optical methods to measure micro-vibrations with instruments like the laser speckle interferometer or to measure the properties of the various masses with instruments measuring refraction.