The JFOPT QSFP-DD 400G (4x100G) 1310nm 2km FR4 LC DX transceiver is a high-performance 400Gb/s Quad Small Form Factor Pluggable-double density (QSFP-DD) optical module designed for optical communication applications over distances of up to 2km. JFOPT continues to invest in optical transceiver production, covering a full range of optical transceiver such as 1*9, SFP, 10G, 25G, 100G, 200G, 400G, 800G GPON/EPON/XG/XGSPON OLT transceiver. At the same time, our company provides TOSA, ROSA, BOSA semi-finished device solutions for the downstream. Abstract: This specification defines: the electrical and optical connectors, electrical signals and power supplies, mechanical and thermal requirements of the pluggable QSFP Double Density (QSFP-DD) module, connector and cage system. This document provides a common specification for systems. QSFP-DD (Quad Small Form-Factor Pluggable Double Density) represents a transformative advancement in optical transceiver technology, addressing the exponential growth in data center bandwidth requirements and the demands of modern high-performance computing environments. The 400G DR4+ optical transmitter is compliant with the IEEE 802. Each optical lane is. The QSFP-DD DCO transceiver provides 400GBASE-ZR throughput up to 120km using EDFA over single-mode fibre (SMF) via an LC/UPC connector. With compliance to OIF MSA standards and multi-vendor interoperability, the module allows interoperability and rapid deployment with other standard-compliant.