Transmission bandwidth of the two-mode fiber link

The transmission bandwidth of the two-mode fiber link is investigated both experimentally and theoretically. It is shown that the experimental bandwidth as a function of wavelength is accurately predicted by using the individual fiber transfer functions and the mode conversion matrix at a splice. The bandwidth is maximized at the wavelength where the overall group delay time difference between the LP01and LP11modes becomes zero, showing the so-called modal equalization effect. It is experimentally certified that the 3 dB bandwidth over 2 GHz is obtained in the wide two-mode-propagation spectral region around 1.3 μm for 5.2 km long two-mode fiber link for the maximum output power launching condition, due to the relatively large attenuation of the LP11mode after long propagation.