1.25G Dual-Port BiDi cSFP 20km Transceiver TX1490/RX1310: 1.25G-cSFP-21-BD

Our EDGEOPTIC 1.25G-cSFP-21-BD is a multi-vendor compatible dual-port compact SFP optical module optimized for high-density Gigabit Ethernet networks operating on the 1490/1310nm wavelength scheme. This cSFP transceiver houses two independent BiDi (Bidirectional) channels within a single standard SFP form factor, allowing network engineers to maximize connectivity per slot while minimizing fiber strand requirements.

The 1.25G-cSFP-21-BD operates with both channels transmitting at 1490nm wavelength and receiving at 1310nm, supporting data rates from 1.063 to 1.25 Gbps per channel. Each channel leverages BiDi technology through WDM (Wavelength Division Multiplexing) to provide full-duplex operation over a single fiber per port. This module functions as the complementary pair to the 1.25G-cSFP-21-AD (TX1310/RX1490), with both units required to complete bidirectional optical links. The 1490/1310nm wavelength combination is particularly relevant for deployments where coexistence with PON systems or specific wavelength allocation requirements must be considered.

The transceiver utilizes DFB (Distributed Feedback) laser transmitters combined with PIN photodiode receivers for each channel. DFB technology ensures excellent wavelength stability and narrow spectral linewidth, essential for reliable 1490nm transmission over extended distances. With transmit power ranging from -9 to +3 dBm and receiver sensitivity of -23 dBm, the module provides a guaranteed 14 dB optical link budget supporting transmission distances up to 20 kilometers over standard single-mode fiber. The receiver accommodates a wide 100nm bandwidth window (1260-1360nm), ensuring robust reception of 1310nm signals. As with all optical modules, actual achievable distance is influenced by fiber plant characteristics, connector quality, and cumulative splice losses.

The 1.25G-cSFP-21-BD features a Double LC/UPC connector interface with two independent optical ports integrated into the compact housing. The electrical interface follows CSFP MSA Option 2 specifications, enabling compatibility with compact SFP-capable host equipment from various vendors.

Full Digital Diagnostic Monitoring (DDM/DOM) functionality provides real-time access to critical parameters including transmitted and received optical power for both channels, module temperature, laser bias current, and supply voltage. These diagnostics support proactive network monitoring and simplified troubleshooting procedures.

The module operates within standard commercial temperature range of 0 to 70°C, suitable for controlled installations such as central offices, data centers, and telecommunications facilities. A single +3.3V supply provides operating power.

Standards compliance includes IEEE 802.3z for Gigabit Ethernet, IEEE 802.3ah for 1000Base-BX20, and 1G Fiber Channel at 1.0625 Gbps for storage networking. Regulatory certifications encompass CE marking, RoHS compliance, and Class 1 laser safety ratings per FDA and IEC 60825-1.

Typical applications include access network aggregation, enterprise campus backbones, and service provider edge deployments where the 1490/1310nm wavelength plan is specified or preferred for infrastructure compatibility reasons.

Because our focus is providing top quality service, we perform comprehensive quality checks including dual-channel optical parameter measurements, connector cleanliness inspection, and EEPROM memory data validation before delivery.