We propose a transmission fiber for mode-division-multiplexed transmission with multiple-input multiple-output (MIMO) digital signal processing supporting four and six linearly polarized (LP) modes over the C + L band. We show numerically that a graded-index core can flexibly tune the differential mode group delay (DMD) and a cladding trench can flexibly control the guiding mode number. We optimized the spacing of the core and trench. Accordingly, we can achieve a few-mode operation of more than two LP modes and low DMD while preventing the high-refractive index difference that leads to manufacturing difficulties and any loss increase. Finally, we successfully fabricated fibers for use in a C + L band WDM-MDM transmission with MIMO DSP, and realized a transmission fiber with a total absolute DMD of less than 40 ps/km for four-LP mode operation and of less than 70 ps/km for six-LP mode operation over the entire C + L band.
© 2014 IEEE
Original Manuscript: March 25, 2014
Manuscript Accepted: May 27, 2014
Published: June 2, 2014
Takayoshi Mori, Taiji Sakamoto, Masaki Wada, Takashi Yamamoto, and Fumihiko Yamamoto, "Few-Mode Fibers Supporting More Than Two LP Modes For Mode-Division-Multiplexed Transmission With MIMO DSP," J. Lightwave Technol. 32, 2468-2479 (2014)