The mode coupling in double-sided tilted gratings between the LP<sub>01</sub> and LP<sub>11</sub> modes is analyzed for three different excitation conditions. It is found that a number of modes, including various LP<sub>11q</sub> modes with different polarization states and TE<sub>01</sub>, TM<sub>01</sub>, and HE<sub>21</sub> modes, can be formed through the mode conversion process in the gratings and with a linear combination of four different LP<sub>11</sub> modes. Efficient single-sided and double-sided tilted gratings are demonstrated. The tilted gratings presented exhibit LP<sub>01</sub>-to-LP<sub>11</sub> mode coupling over a spectral width as wide as 160 nm. The transmission spectra of the tilted fiber gratings agree well with the spectrum predicted by the coupled-mode analysis.
© 2001 Optical Society of America
(050.2770) Diffraction and gratings : Gratings
(060.0060) Fiber optics and optical communications : Fiber optics and optical communications
(060.2340) Fiber optics and optical communications : Fiber optics components
Kyung Shik Lee and Turan Erdogan, "Fiber mode conversion with tilted gratings in an optical fiber," J. Opt. Soc. Am. A 18, 1176-1185 (2001)