Corning Incorporated
MODE EXPANSION WAVEGUIDE AND SPOT SIZE CONVERTER COMPRISING SUCH FOR DIRECT COUPLING WITH FIBER

Abstract:

A waveguide comprising: a tapered-width first waveguide portion and second waveguide portions and a third waveguide portion, such that along a first direction, widths of a first and the second waveguide portions gradually increase towards a first end of the third waveguide portion, and a distance, in a second direction, between the first waveguide portion and the second waveguide portion gradually decreases from a second end of the first waveguide portion to the first end of the first waveguide portion, wherein the second direction is perpendicular to the first direction; and the maximum distance Gmax between the second end of the first waveguide portion and a second end of the second waveguide portion is greater than 0.2 .mu.m and less than 0.48 .mu.m; and the waveguide has a refractive index between 2 and 4 at a 1550 nm wavelength.