Can a laser powerful enough to cut(100w for example) be redirected using fiber optics ? What issues need to be considered?
To be clear it should retain the ability to cut after exiting the fiber.
Yes easily. Fiber-fed 5-10kW Nd-Yag lasers are commonly used for cutting metal in machine shops. Fibers are so transparent, especially when designed for a single wavelength laser, that the power loss and so heating in the fiber is very small. It's generally less than an optically fed laser where dirt accumulates on the lenses.
Many systems have a thin fiber wrapped around the main power delivery fiber with a small low power laser diode shining through it. If there is a fault in the main fiber, the high power laser beam will leak out and cut the thinner fiber. The loss of light in the wrapping fiber signals the controller to kill the power to the main laser.