Fiber-optic mode converter with a narrow-band or broadband spectrum

The spectral properties of a LP(01) ? LP(02) mode converter by using a photoinduced fiber grating are investigated. A fiber with given parameters is considered, and the wavelength dependence of power conversion between the two modes is calculated. The results show that the spectrum can be narrowed by selecting the operating wavelength close to the cutoff wavelength of the LP(02) mode. The methods for obtaining a mode converter with a broadband spectrum and a mode converter with a spectrum having two peaks are also discussed.