Currently, the global 5G network, cloud computing, and data center industries are experiencing rapid development. The continuous growth of data center traffic has driven the vigorous progress in high-speed optical transceivers for optical interconnection within data centers. The electro-absorption modulated laser (EML), which is widely used in optical fiber communications, data centers, and high-speed data transmission systems, represents a high-performance photoelectric conversion device. Compared to traditional directly modulated lasers (DMLs), EMLs demonstrate lower frequency chirp and higher modulation bandwidth, enabling support for higher data rates and longer transmission distances. This article introduces the composition, working principles, manufacturing processes, and applications of EMLs. It reviews the progress on advanced indium phosphide (InP)-based EML devices from research institutions worldwide, while summarizing and comparing data transmission rates and key technical approaches across various studies.

The mechanism of the etching process that ensures high yield in spin-orbit torque magnetic random-access memory (SOT-MRAM) featuring a novel channel-less (CHL) structure is systematically investigated in this paper. A steep sidewall morphology is identified as particularly favorable, and the precise relationship between the pillar profile and yield is established and thoroughly analyzed. When the step angle exceeds 80°, a larger net etching rate along the sidewall is achieved, enabling effective removal of metal residues near the tunnel barrier layer while minimizing plasma-induced damage at the MgO/CoFeB interface. The optimized devices exhibit an excellent thermal stability factor (Δ) of over 95 at room temperature, demonstrating superior operational reliability. Thanks to process optimizations targeting re-deposition removal, the in-die functional yield of the fabricated 16 Kb CHL SOT-MRAM array reaches an impressive 60 ppm. These advancements pave the way for high-yield and reliable mass production of SOT-MRAM devices.