Patent ID: 6928223

Claim:
A laser and optical amplifier device comprising: a waveguide having a plurality of layers of semiconductor material with different optical indices, the waveguide including a first heightened region in a first of said layers, the first heightened region forming a channel along a longitudinal axis within which a lowest order spatial mode in both lateral and transverse directions is supported; an active region within a second layer near the first heightened region of the waveguide that is pumped to provide gain for said lowest order spatial mode in said waveguide; and first and second lateral regions, extending parallel to and on each side of said first heightened region along the longitudinal axis, into which all higher order spatial modes extend laterally and are suppressed, wherein the cross-sectional dimensions of the lowest order spatial mode are at least several times larger in both the transverse and lateral directions than the optical wavelength inside a dielectric medium of the waveguide.