Small fusion reactors don't really solve any of the key challenges. You need reaction mass to accelerate, you run out of reaction mass way too quickly even with a magical energy source on board to throw it out the back of the ship really fast.
why, so they can watch corporate news from earth to get depressed? /s
Actually, it's a great question. Even if we have single photon sensitivity detectors, just what kind of power would a laser need? Or would it be some other area of the emf spectrum? Or some other kind of communication? Sci fi ventures into gravitational waves sometimes
And work out safe systems for hibernation, maybe rotate the crew in shifts
Oh yeah this is the stuff of science fiction coming to life