Since the 1970s, the transmission capacity of a single optical fiber has increased exponentially, from 10G per channel to 100T per channel. Technologies such as Time Division Multiplexing technology (TDM), Wavelength Division Multiplexing (WDM), Optical Amplification (EDFA), and Digital Coherent Technology, etc. has been born successively. The fiber capacity is reaching its limitation due to the Nonlinear Shannon Limit. Based on this background, researchers proposed Space Division Multiplexing technology (SDM) and produced multi-core fibers, aiming to solve the carrying capacity of a single optical fiber.
Fig.1 System capacity per optical fiber
Currently, common multi-core optical fibers include 2-core, 4-core, 7-core, 8-core, 19-core, etc., for different applications. 2-core MCF has been widely used in submarine cabling, and the development of 4-core MCF has become a hot trend.
Fig.2 Types of Multi-core Fiber
According to Business Research Insights, the usage of MCF-related optical fibers will reach a market size of 9.8543 billion USD by 2028, with demand for 4-core and 7-core fibers being the largest.
Fig.3 Global Multi-core Fibers Market Size
To achieve practical use of MCF, spatial multiplexers/demultiplexers known as fan-in/fan-out (FIFO) devices that efficiently couple light from single-core fiber (SCF) into each multi-core fiber (MCF) or the opposite direction. So far, a variety of FIFO device implementation technologies have been reported, but the most commonly used technologies are: 1) fused tapering technology; 2) 3D waveguide technology; and 3) free space optical technology.
Fig.4 FIFO device implementation technologies
Based on advanced free-space optical design capabilities and mature precision coupling capabilities, HYC has launches a compact and low crosstalk four-core MCF fan-in/fan-out (FIFO) devices. Optical components such as lens and prisms are precisely designed to adjust and optimize the coupling between MCF and SCF to achieve compact structure and excellent indicators. This FIFO device with a 43um core-to-core spacing has low average coupling loss (<0.5dB), low crosstalk (>45dB), and return loss (>55dB).
With the development of 5G, AIGC, Cloud Computing, the demand for optical fiber transmission capacity is also increasing. Multi-core optical fiber with Space Division Multiplexing (SDM) technology is expected to become the best choice to break through the Nonlinear Shannon Limit of traditional single-core optical fiber. Fan-in/Fan-out FIFO device is the key component connecting multi-core optical fiber and single-core optical fiber. Based on this MCF FIFO development platform, HYC will soon launch MCF with larger channels, such as 7CH, 8CH, and even 19CH.