Light only bends space-time because it has energy,just like anything else. It is no more effective than ordinary matter (from an Engineering prospective, it would be worse than ordinary matter, because ordinary matter has rest mass and can be stored easily).

There has been some speculation of enabling some form of hyperspace by reducing the distance between two points for a vessel to travel.Worm holes are another popular speculation. The fact is that both of these depend on theories of quantum mechanics applied to gravity, and no evidence of these has ever been observed. Because matter behave saccording to quantum mechanics and gravity both, the two areas of physics MUST mesh somehow, but the exact details of that are utterly unknown. I think I can safely say that who ever figures it out is going to get the Nobel Prize.

If light can indeed twist space-time, the effect is extremely small. A spinning object can twist space-time, which was predicted by Einstein and recently verified by the Gravity Probe B experiment:
click here .

Earth is a pretty large, spinning object, but it took 22 years to come up with an experiment that could measure its twist of space-time. And it's not clear (at least not to me) that light can be made to twist space-time at all. Another problem with using light to generate an Alcubierre warp drive is that you have to confine the light somehow, like with a set of mirrors. But the mirrors are outside the bubble, so they can't go any faster than the speed of light, which means the bubble itself can't go the speed of light.