The mode coupling in double-sided tilted gratings between the LP01 and LP11
modes is analyzed far three different excitation conditions. It is found t
hat a number of modes, including various LP11q modes with different polariz
ation states and TE01, TM01, and HE21 modes, can be formed through, the mod
e conversion process in the gratings and with a linear combination of four
different LP11 modes. Efficient single-sided and double-sided tilted gratin
gs are demonstrated. The tilted gratings presented exhibit LP01-to-LP11 mer
le coupling over a spectral width as wide as 160 nm. The transmission spect
ra of the tilted fiber gratings agree well with the spectrum predicted by t
he coupled-mode analysis. (C) 2001 Optical Society of America.