Analysis of random grating period and amplitude errors in ultra-thin long-period grating

The effects of random fabrication errors on an ultra-thin long-period grating are numerically investigated. The influences of the random grating period and random amplitude nodes on an optical bandpass filter based on an ultra-thin long-period grating are introduced. It is found that the random period errors present severe degradation of the spectral performance of the ultra-thin long-period grating. The coupling intensity of the ultra-thin long-period grating decays exponentially with even small grating period noises. Our simulation results may help manufacturers to analyze the quality of fabricated long-period gratings and to point out future improvement directions.