1.25G Dual-Port BiDi cSFP 40km Transceiver TX1550/RX1310: 1.25G-cSFP-40-BD

Our EDGEOPTIC 1.25G-cSFP-40-BD is a multi-vendor compatible dual-port compact SFP optical module engineered for extended-reach Gigabit Ethernet deployments requiring doubled port density. This cSFP transceiver integrates two independent BiDi (Bidirectional) channels within a single standard SFP footprint, enabling network engineers to maximize connectivity while reducing both rack space and fiber infrastructure requirements over metropolitan distances.

The 1.25G-cSFP-40-BD operates with both channels transmitting at 1550nm wavelength and receiving at 1310nm, supporting data rates from 1.063 to 1.25 Gbps per channel. Each channel utilizes BiDi technology with WDM (Wavelength Division Multiplexing) to achieve full-duplex communication over individual fiber strands. This module serves as the complementary pair to the 1.25G-cSFP-40-AD (TX1310/RX1550), and both units are required to establish functional bidirectional optical links.

The 40km reach capability sets this transceiver apart from its 20km counterparts, addressing network requirements spanning metropolitan access rings, extended campus interconnects, and carrier aggregation applications. This extended distance is achieved through enhanced optical specifications, with transmit power ranging from -5 to 0 dBm and improved receiver sensitivity of -24 dBm, delivering a guaranteed 19 dB optical link budget. The 5 dB improvement over 20km variants provides the additional margin necessary to overcome fiber attenuation and connector losses across longer spans.

The transceiver employs DFB (Distributed Feedback) laser transmitters paired with PIN photodiode receivers for each channel. DFB lasers provide the narrow spectral width and wavelength stability essential for extended-reach 1550nm transmission, where chromatic dispersion becomes increasingly significant. With dispersion tolerance of 800-1000 ps/nm, the module accommodates the accumulated dispersion typical of 40km single-mode fiber spans. However, actual achievable distance remains dependent on fiber plant characteristics, connector quality, and cumulative splice losses.

The 1.25G-cSFP-40-BD features a Double LC/UPC connector interface accommodating two separate optical ports within the compact enclosure. The electrical interface conforms to CSFP MSA Option 2 specifications, ensuring seamless integration with compatible host equipment from multiple vendors.

Digital Diagnostic Monitoring (DDM/DOM) functionality provides comprehensive real-time visibility into operational parameters including transmitted and received optical power for both channels, module temperature, laser bias current, and supply voltage. This diagnostic capability enables proactive network management and efficient troubleshooting across extended network segments.

The module operates within standard commercial temperature range of 0 to 70°C, suitable for controlled environments including central offices, data centers, and telecommunications facilities. Power is supplied via a single +3.3V rail.

Standards compliance includes IEEE 802.3z for Gigabit Ethernet, IEEE 802.3ah for 1000Base-BX applications, and 1G Fiber Channel at 1.0625 Gbps. Certifications encompass CE marking, RoHS compliance, and Class 1 laser safety per FDA and IEC 60825-1 standards.

Typical deployment scenarios include metropolitan area network aggregation, inter-building campus connectivity spanning multiple kilometers, service provider access networks, and enterprise WAN links where the combination of extended reach, port density, and fiber conservation delivers operational advantages.

Because our focus is providing top quality service, we perform thorough quality verification including optical parameter measurements for both channels, connector cleanliness inspection, and EEPROM memory data validation before delivery.