The DirectXTK or DirectX Tool Kit is a bunch of classes that you can reuse in your game design if you want to implement a game engine for specific work effort. One of the confusing problem that many have with C++/CX DirectX is: Why? You could use Unity or a purchased Game Engine. But that is the reason, usually there are costs that can be significant, which is a good thing for many designers. But there is always room for another improved game engine.
And if you want to get known as a hot shot developer who attracts intelligent designers, then a game engine you can own and understand deeply is a good way to show off your skills in software design, test management, and version control. Later you could keep costs down by developing your own line of games for a number of platforms.
I never get the whole “optics” thing, but thought it sounded cool. First download the DirectXTK from Codeplex:DirectX Tool Kit , the tool kit will be maintained at that link which works as of Sept. 4, 2013.
Documentation for the DirectX Tool Kit can be found at: http://directxtk.codeplex.com/wikipage?title=DirectXTK&referringTitle=Documentation
Some links that are also duplicated at: http://directxtk.codeplex.com/wikipage?title=Resources&referringTitle=Documentation