Long distance transmission in few-mode fibers

Abstract

Using multimode fibers for long-haul transmission is proposed and demonstrated experimentally. In particular few-mode fibers (FMFs) are demonstrated as a good compromise since they are sufficiently resistant to mode coupling compared to standard multimode fibers but they still can have large core diameters compared to single-mode fibers. As a result these fibers can have significantly less nonlinearity and at the same time they can have the same performance as single-mode fibers in terms of dispersion and loss. In the absence of mode coupling it is possible to use these fibers in the single-mode operation where all the data is carried in only one of the spatial modes throughout the fiber. It is shown experimentally that the single-mode operation is achieved simply by splicing single-mode fibers to both ends of a 35-km-long dual-mode fiber at 1310 nm. After 35 km of transmission, no modal dispersion or excess loss was observed. Finally the same fiber is placed in a recirculating loop and 3 WDM channels each carrying 6 Gb/s BPSK data were transmitted through 1050 km of the few-mode fiber without modal dispersion.

Mode Conversion for Mode Division Multiplexing at 850 nm in Standard SMF

“…The elimination of this connector by using the same fiber in the converter and in the fiber span would avoid any potential mode crosstalk. No mode crosstalk is expected to be due to the mode coupling along the fiber as the difference between the effective indexes of both modes is 1.3·10 -3 [13]. In order to test the link capability along 1 km we will transmit the individual modes modulated by an OOK signal with a 2 31 -1 pseudo random bit sequence (PRBS) at 1.25 Gb/s and 2.5 Gb/s.…”

Mode-dependent loss measurement of a two-mode fiber using a conventional OTDR

“…Space-division multiplexing using multi-core fibers or few-mode fibers (FMFs) is a powerful and promising technology that can overcome the capacity limit of a single-mode fiber [1,2,3]. FMFs support more than one propagation mode.…”

Mode demultiplexer using angularly multiplexed volume holograms

“…By contrast, the MDM systems distinguish the spatial modes as individual channels, and therefore, independently modulated signals in different modes are transmitted by multiplexing and are received after being separated into respective modes, without pulse broadening. Recently, high-performance fibers for MDM, such as few-mode fibers, have been studied and reported [4][5][6][7][8][9]. In addition, the technologies to excite a specific spatial mode in an optical fiber have been studied [10][11][12][13][14], in which mode multiplexing or demultiplexing is performed by using parallel connected and nested devices, such as phase plates and mode couplers, because, in general, each of these devices can separate only one spatial mode.…”