1.25G Dual-Port BiDi cSFP 20km Transceiver TX1310/RX1490: 1.25G-cSFP-21-AD

Our EDGEOPTIC 1.25G-cSFP-21-AD is a multi-vendor compatible dual-port compact SFP optical module designed for high-density Gigabit Ethernet deployments utilizing the 1310/1490nm wavelength scheme. This cSFP transceiver integrates two independent BiDi (Bidirectional) channels within a single standard SFP footprint, enabling network engineers to double port capacity while conserving valuable rack space.

The 1.25G-cSFP-21-AD operates with both channels transmitting at 1310nm wavelength and receiving at 1490nm, 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 must be deployed with its complementary counterpart, the 1.25G-cSFP-21-BD (TX1490/RX1310), to establish functional bidirectional links. The 1310/1490nm wavelength pairing offers an alternative to the 1310/1550nm scheme, providing flexibility for network designs where wavelength planning or existing infrastructure considerations dictate specific optical windows.

The transceiver employs FP (Fabry-Perot) laser transmitters paired with PIN photodiode receivers for each channel. With transmit power ranging from -9 to -3 dBm and receiver sensitivity of -23 dBm, the module delivers a guaranteed 14 dB optical link budget. This enables transmission distances up to 20 kilometers over standard single-mode fiber, suitable for metropolitan access and campus backbone applications. The receiver operates within a narrow 20nm bandwidth window (1480-1500nm), optimized for the 1490nm reception wavelength. Actual transmission distance depends on fiber plant quality, connector losses, and splice attenuation specific to each installation.

The 1.25G-cSFP-21-AD 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 compatibility with host systems designed for compact SFP modules across multiple vendor platforms.

Digital Diagnostic Monitoring (DDM/DOM) is fully supported, enabling real-time visibility into transmitted and received optical power levels for both channels, module temperature, laser bias current, and supply voltage. This diagnostic capability facilitates proactive network management and efficient fault isolation.

Operating temperature range spans 0 to 70°C for standard commercial environments including central offices and equipment rooms. The module requires a single +3.3V power supply.

Standards compliance includes IEEE 802.3z for Gigabit Ethernet and IEEE 802.3ah for 1000Base-BX20 applications, along with 1G Fiber Channel support at 1.0625 Gbps. The transceiver holds CE and RoHS certifications with Class 1 laser safety compliance per FDA and IEC 60825-1 standards.

Typical deployment scenarios encompass FTTH/FTTB access networks, campus distribution layers, and carrier aggregation points where the 1310/1490nm wavelength plan aligns with existing infrastructure or PON coexistence requirements.

Because our focus is providing top quality service, we conduct thorough quality verification before delivery, including optical parameter measurements, connector cleanliness testing, and EEPROM memory data validation.