OPTICAL DEVICE THAT INCLUDES AN EPITAXIAL LAYER STRUCTURE WITH TRENCHES AND GROOVES

An optical device includes a substrate and an epitaxial layer structure disposed over the substrate. The epitaxial layer structure includes a first clad layer disposed over the substrate, a first waveguide layer disposed over the first clad layer, an active layer disposed over the first waveguide layer, a second waveguide layer disposed over the active layer, a second clad layer disposed over the second waveguide layer, and a cap layer disposed over the second clad layer. The optical device further includes a pair of trenches formed in an inner region of a surface of the epitaxial layer structure, and a pair of grooves, each formed in an outer region of the surface of the epitaxial layer structure. Each trench does not extend into the active layer, and each groove extends into the active layer. A light-current curve associated with the laser optical device is kink-free and/or smooth.