Use of Optically Controlled Phase Shifters?

If you're talking "optical" check out "waveplates." Zero order waveplates are the best to use without temperature control, and they come in both ¼ and ½ wave retardation. Try Thorlabs for information.

You say "optically controlled phase shifters". Are you talking about phase shifters for RF/microwave where the phase can be adjusted/controlled by the intensity of incident light? Or are you talking about optical delay lines that carry RF signals? I have seen papers on both of these for use in phased-array applications - though I have no idea whether they have proved to be advantageous over more established techniques in practice.

Fyz