Patent ID: 7840098

Claim:
An apparatus, comprising: an optical waveguide including a slab region and a rib region formed from a layer of substrate semiconductor material, wherein the rib region includes intrinsic silicon, an optical beam to be directed through the optical waveguide such that the optical beam propagates through the intrinsic silicon of the rib region, the optical beam to generate free carriers in the optical waveguide via two-photon absorption in response to an input power level of the optical beam; and a reversed-biased PIN diode structure disposed in the optical waveguide, the reverse-biased PIN diode structure including an electric field between a P region and an N region of the reverse-biased PIN diode structure to sweep out free carriers from the optical waveguide to control free carrier lifetimes of the free carriers in the optical waveguide to limit an output power of the optical beam to a clamped output power level in response to the electric field of the reverse biased diode structure such that substantially all of the optical beam propagates through the optical waveguide when the input power level of the optical beam is substantially less than the clamped output power level and such that the output power of the optical beam is clamped to the clamped output power level when the input power level is greater than the clamped output power level, wherein the intrinsic silicon of rib region is disposed directly on intrinsic silicon of the slab region without a layer of dielectric material intervening between the intrinsic silicon of the rib region and the intrinsic silicon of the slab region.