Traditional optical fiber has glass in the middle. The speed of light in glass is only about 66% of the speed in air, so microwave is always faster if you can get a reasonably straight path for both.
There now exists hollow-core fiber, where the light travels down an air gap in the middle, which is theoretically competitive with microwaves/lasers/etc. How much this is being used is a secret, but microwave transmission definitely hasn't gone away.