Randomly-coupled multi-core fiber (MCF) technology has come to attract lots of attention because of its strong applicability to long-haul transmission systems. Compared with weakly-coupled MCFs with independent cores, it can simultaneously realize higher spatial channel density and ultralow transmission loss using existing ultralow-loss single-mode fiber (SMF) core designs. The strong mode coupling characteristics of randomly-coupled MCFs can provide favorable optical properties, such as suppressed accumulation of modal dispersion (MD), mode-dependent loss (MDL), and nonlinear impairments. This article gives an overview of randomly-coupled MCF technology advancements. First, we describe the classification and design of randomly-coupled MCFs and explain what the randomly-coupled MCFs are and how they are designed. State-of-the-art randomly-coupled MCFs can accommodate four, seven, or 12 cores in a standard 125-$\mu \text{m}$cladding while achieving ultralow transmission loss and/or small MD, which are very promising for long-haul transmission media. Next, we present the methods to characterize the optical properties of randomly-coupled MCFs and the difference compared to conventional SMF measurements. We also show the low-loss low-MDL connectivity of this type of MCF and the cabling that can suppress MD. A field-deployed randomly-coupled MCF cable testbed is also presented, which confirmed the favorable optical properties of randomly-coupled MCFs after deployment. Then, multi-core amplifier technologies are briefly summarized, and finally, we discuss the performance improvements in the transmissions over randomly-coupled MCFs and suitable application areas.

In practical courses on software-intensive business systems, students work in teams to acquire practical skills in systems acquisition and provisioning. However, we do not yet have an established method to determine the optimal team composition to achieve maximum educational effectiveness. In this study, we quantitatively and qualitatively investigate how personal characteristics and the learning process of team members affect educational effectiveness by examining a university course in which students work in teams on a realistic project in a classroom setting. We use the Five Factors and Stress (FFS) theory and the modified grounded theory approach (M-GTA) to measure the personal characteristics and to identify the learning process of each team member. Additionally, we compare the learning process of a team with a high educational effectiveness to one with a low educational effectiveness based on number of topics about the learning process and the kind of topics. As a result, we find that it is better for a team to have members with different personal characteristic as defined by FFS theory in order for the students to acquire more knowledge and skills through the course. Additionally, teams that focus on fewer learning process topics acquire more knowledge and skills. We expect that our findings will help increase the educational effectiveness in similar practical courses.