90 degree optical coupling

I am looking for ways of coupling light from one optical waveguide or fiber to another, that are 90 degrees angle from each other.
Some people suggest using small mirrors, but that would require few um dimensional and positional accuracy. I am looking for something that can be made cheaply and easily.

I am thinking on using some glue that is white milk-like (similar to fluorescent light tube coating), lets light through but scatters it in all direction, gluing the 2 fibers together, than using another glue around the structure that is chrome or silver color to reflect everything back from the milk-glue and fiber surfaces. Would this work?

Should it be mechanical ?
I think it's easier to shift 90 degree by converting optical-electrical-optical.
There will certainly be a calibration mechanism but I guess mechanical shifting is harder due to small dimensions.
Just an idea..

Thanx. It has to be optical-only.