3D waveguide device for few-mode multi-core fiber optical communications

Abstract

Space-division multiplexing based on few-mode multi-core fiber (FM-MCF) technology is expected to break the Shannon limit of a single-mode fiber. However, an FM-MCF is compact, and it is difficult to couple the beam to each fiber core. 3D waveguide devices have the advantages of low insertion loss and low cross talk in separating various spatial paths of multi-core fibers. Designing a 3D waveguide device for an FM-MCF requires considering not only higher-order modes transmission, but also waveguide bending. We propose and demonstrate a 3D waveguide device fabricated by femtosecond laser direct writing for various spatial path separations in an FM-MCF. The 3D waveguide device couples the LP01 and LP11a modes to the FM-MCF with an insertion loss below 3 dB and cross talk between waveguides below − 36 dB . To test the performance of the 3D waveguide device, we demonstrate four-channel multiplexing communication with two LP modes and two cores in a 1-km few-mode seven-core fiber. The bit error rate curves show that the different degrees of bending of the waveguides result in a difference of approximately 1 dB in the power penalty. Femtosecond laser direct writing fabrication enables 3D waveguide devices to support high-order LP modes transmission and further improves FM-MCF communication.

Research on the architecture design of optical fiber communication digital twin system and its key technology

“…The multi-dimensional fusion sensing technology of optical fiber physical layer includes data extraction, fusion architecture design and fusion algorithm. [9] To fully utilize the information from the network and links, a two-stage fault monitoring and localization algorithm is proposed using data source fusion in the fusion algorithm. In the first stage, the mean, standard deviation, minimum and maximum value of the equalizer tap, the center frequency of the digital domain spectrum in the terminal DSP are used as the input parameters of the neural network to monitor the fault and output rough positioning results.…”

Bessel-beam-based side-view measurement of seven-core fibre internal core distribution

“…These fibres comprise multiple cores arranged in a geometrically symmetrical pattern within a single cladding to minimize inter-core crosstalk 10,11 . The core distribution positioning during fibre processing, such as fibre splicing 12,13 , bundle fan-in/fanout 14,15 , mode coupling 16,17 , writing grating 18,19 , and fibre drawing 20,21 , must be precise as it determines the working performance, including loss and response. In the case of fibre splicing, bundle fan-in/fan-out, and mode coupling, precise core alignment minimizes loss, thereby significantly improving the quality and capacity of the transmitted signal 22 .…”