【Abstract】The capacity expansion of short-distance optical fiber transmission systems has received increasing attention . Space division multiplexing optical transmission technology provides two new dimensions of fiber core and mode, which can greatly increase the transmission capacity of a single optical fiber. However, the crosstalk between spatial channels severely limits the practical application of spatial division multiplexing technology. First, a weakly coupled space-division multiplexing fiber was studied, and effective separation between modes was achieved by introducing annular refractive index perturbations in the fiber core. Secondly, an all-fiber complex that can handle non-circularly symmetric degenerate modes was proposed. Use/demultiplex devices and low insertion loss, low crosstalk fan-in and fan-out devices; on this basis, low-cost commercial intensity modulation is used to directly detect the optical module to achieve short-distance weak coupling mode division multiplexing and multi-core few modes. Multiplexing real-time optical transmission; finally, the spatial division multiplexing real-time optical transmission technology is prospected.
【Keywords】Few-mode fiber; space division multiplexing; real-time optical transmission a>
0 Preface
With the continuous development of technologies such as 5G mobile bearer optical network, data center optical interconnection and optical fiber access network, short-distance optical fiber transmission technology has received more and more widespread attention. The choice of technical solutions is limited by cost and complexity. Short-distance optical transmission generally can only use intensity modulation and direct detection (IM/DD) solutions, and electrical domain high-speed digital signal processing (digital signal processing) cannot be used. processing, DSP) technology to improve performance, the transmission rate is seriously limited by optoelectronic devices; in terms of multiplexing dimension, currently only the wavelength dimension can be used, and the high cost of multi-wavelength lasers and wavelength division multiplexers makes wavelength division multiplexing It is difficult to apply on a large scale in short-distance scenarios. Therefore, a large number of short-distance application scenarios such as data centers have to use the simplest way to increase capacity, that is, using multiple optical fibers for low-rate parallel transmission. However, as the demand for transmission capacity further increases, the disadvantages of multi-channel optical fiber parallel transmission solutions in terms of system size, power consumption and cost have become increasingly prominent, and it is imperative to adopt new expansion methods.