A solid-state light source has a wavelength conversion chip affixed to a light emitting diode. The LO generation schemes presented are operative to generate I and Q square waves at a designated frequency while avoiding the well known issue of harmonic pulling. A further method includes the steps of forming a bottom oxide layer on a substrate, depositing a nitride layer, depositing a portion of a top oxide layer and oxidizing a remaining portion of the top oxide layer, thereby causing oxygen to be introduced into the nitride layer. In some embodiments the nerve is modulated in response to a physiological parameter.