Aperture synthesis, aka interferometry, has been applied to optical systems for far more than 15 years. The Narrabri Stellar Intensity Interferometer[1] saw first light in 1963, for example. However, your resolving power is still fundamentally limited by the distance between your telescopes. The diffraction limit may be more of a fuzzy limit than a hard cut off, but it is fundamental physics. Optical interferometry is hard, and you don't get a image in the way that most people would think of it. To build up a detailed image with aperture synthesis requires measurements over a very large number of baselines.

[1] https://en.wikipedia.org/wiki/Narrabri_Stellar_Intensity_Int...