Reduced cladding mode losses in tilted gratings that are rotationally symmetric

We present a novel method to manipulate mode coupling by using tilted grati ngs written in standard fiber that is rotated during the writing process. W e show theoretically that such gratings exhibit significantly reduced trans mission losses in the 15-nm wavelength range below the main core-to-core re flection peak. By combining with existing methods, cladding mode losses can be further reduced.