Patent ID: 8411353

Claim:
An optical frequency converter comprising: an optical guiding structure having an input for inputting a fundamental harmonic signal and an output for outputting a second harmonic signal, and comprising: a first grating portion adjacent to said input; a second grating portion adjacent to output, and a third grating portion between said first and second grating portions to form an apodized step-chirped grating extending between said input and said output, each one of said first, second, and third grating portions comprising a plurality of sections each comprising a plurality of segments, each segment having a segment width and comprising a poled region having a poled width at least equal to one micron and a reversely poled region, said segment width for said first, second, and third grating portions and a duty ratio of said poled width to said segment width being constant within each one of said sections, said segment width increasing from one of said sections to a following one of said sections from said input towards said output, said duty ratio increasing from one section to a following one within said first grating portion, decreasing from one section to a following one within said second grating portion, and being constant within said third grating portion.