Apodization profile amplification of silicon integrated Bragg gratings through lateral phase delays

It is shown that an apodization profile to realize a specific spectral response for a silicon integrated Bragg grating (IBG) can be amplified/scaled-up greatly by an order of magnitude by introducing phase delays between the two sides of the apodized gratings. This amplification brings about significant improvements in the apodization dynamic range and resolution/precision, thereby facilitating the spectral tailoring of the IBGs. The concept is first exploited in corrugation width-modulated Gaussian-apodized silicon IBGs, and then in phase-modulated silicon IBGs to achieve a five-channel dispersionless square-shaped filter. Significant spectral performance improvements brought by the amplification are demonstrated in both cases.