An optoelectrode having a lens optically coupled between a light source and a light guide and a method of making an optoelectrode. In one embodiment of the optoelectrode, the lens is a gradient index (GRIN) lens and the light source is a side-emitting injection laser diode (ILD). The optoelectrodes can be implemented such that they are high density, highly compact, monolithically integrated, and can deliver multicolor light output independently and simultaneously at a common waveguide port using an optical mixer, for example. In a preferred embodiment, the optoelectrodes are used as neural probes.
