Patent ID: 7755978

Claim:
A recording head which uses light for information recording to a recording medium, comprising: a slider which has a structure to move relative to the recording medium while floating thereon; and an optical waveguide which is provided in the slider, wherein the optical waveguide comprises a core and a cladding and the optical waveguide has a refractive index difference of 20% or more between the core and the cladding, wherein the core has a first portion at a light output side of the optical waveguide and a second portion at a light input side of the optical waveguide, wherein the first portion extends along a direction in which light is guided within the optical waveguide and the first portion has 1) a width that is constant along a first direction perpendicular to the direction in which light is guided within the optical waveguide and 2) a height that is constant along a second direction that is perpendicular to both the first direction and the direction in which light is guided within the optical waveguide, and wherein the second portion extends along the direction in which light is guided within the optical waveguide and the second portion has a width that widens in the direction in which light is guided within the optical waveguide.