25GBASE-CSR SFP28 400m MMF Transceiver: 25G-SFP28-400

Our EDGEOPTIC 25G-SFP28-400 is a multi-vendor compatible 25GBASE-CSR SFP28 dual-fiber optical module designed for cost-optimized short-reach 25 Gigabit Ethernet applications operating over multimode fiber cabling. The 25G-SFP28-400 module operates at 850nm wavelength for both transmission and reception, with data rates from 8.5 to 28.1 Gbps supporting multiple protocol standards and applications. Our 25GBASE-CSR SFP28 transceiver utilizes VCSEL (Vertical-Cavity Surface-Emitting Laser) technology for transmission and PIN photodiode for receiving, engineered specifically for extended multimode reach in large-scale data center deployments.

The transceiver ensures a 5.3 dB guaranteed optical link budget with host-based Forward Error Correction (FEC) support, which determines the maximum transmission distance capabilities. Over OM3 multimode fiber, the module achieves 300 meters reach, while OM4/OM5 cabling extends transmission distance up to 400 meters, providing significantly enhanced reach compared to standard SR transceivers. However, distance is just an indicative parameter calculated for convenience of identification – eventually we calculate distance taking into account minimal optical budget and average attenuation of optical cabling in industry standards. The FEC support is essential for achieving the extended 400-meter reach, correcting transmission errors to maintain signal integrity across larger data center fabrics.

25G-SFP28-400 compatible 25GBASE-CSR module is hot-pluggable SFP28 with duplex LC/UPC connectors as an optical interface. The electrical interface conforms to SFF-8431 and SFF-8432 MSA (Multi-Source Agreement) specifications, ensuring compatibility with standard SFP28 host systems supporting multiple vendor equipment platforms. Our 25GBASE-CSR SFP28 transceiver can be encoded to be compatible and successfully operate in different 80+ brands of equipment. The module incorporates comprehensive DDM/DOM (Digital Diagnostic Monitoring) functionality providing real-time information including transmitted and received optical power levels, module temperature, bias current, and supply voltage. This diagnostic data is available via MSA-compatible EEPROM interface per SFF-8472 specifications, enabling continuous monitoring of transceiver operational parameters critical for extended-reach multimode applications.

The module operates within a 0 to 70°C temperature range with exceptionally low power consumption of 0.3W maximum, making it ideal for high-density deployments in hyperscale data centers. The VCSEL laser technology provides robust output power from -5 to 2.4 dBm with minimum extinction ratio of 3 dB, while the PIN photodiode receiver maintains sensitivity up to 2.4 dBm with enhanced receiver overload protection at 3.4 dBm, accommodating the stronger signals typical in extended multimode applications. The 20nm receiver wavelength bandwidth ensures proper signal reception while maintaining optimal performance. Standards compliance includes SFP28 MSA specifications, supporting both 10G Ethernet (10.31 Gbps) and 25G Ethernet (25.78 Gbps) applications. The transceiver achieves multi-vendor interoperability through adherence to industry standards, though equipment with vendor-specific module validation may require custom EEPROM programming for compatibility.

Our 25G SFP28 CSR transceiver is CE/RoHS certified and compliant with Class 1 FDA and IEC60825-1 laser safety standards. Typical applications include hyperscale data center deployments, extended-reach top-of-rack connections, inter-rack connectivity in large data halls, high-performance computing clusters, and cloud infrastructure requiring greater reach than standard SR transceivers. The CSR specification provides the optimal balance between cost-effectiveness and extended reach, eliminating the need for expensive single-mode infrastructure in medium-distance data center applications. The multi-rate capability accommodates legacy 10 Gigabit Ethernet operation alongside native 25 Gigabit rates, providing operational flexibility for mixed-speed network deployments. Because our focus is providing top quality service, we perform rigorous quality checks before delivery including optical parameter measurements, FEC compatibility testing, connector cleanliness tests, and SFP28 transceiver EEPROM memory data validation tests, ensuring reliable 400-meter transmission over multimode fiber.