2.5G CSFP Optical Module for 20km BiDi Transmission

1. What Is a 2.5G CSFP Optical Module?

With the rapid growth of FTTH broadband access, industrial communications, and enterprise fiber networks, network designers are increasingly demanding higher port density and better space utilization.

CSFP (Compact Small Form-factor Pluggable) is a compact optical transceiver format that integrates two independent optical channels within a standard SFP-sized package.

Compared with traditional SFP modules, CSFP enables dual-channel communication in a single port, significantly improving interface utilization and deployment density.

Similar to CSFP architecture, C-LIGHT also offers SFP56-DD and DSFP56 product series, which integrate dual independent optical and electrical channels in a single module design.

2. Why Is CSFP Technology Favored by Telecom Operators?

Traditional SFP modules support one service per port.

CSFP technology enables:

• Dual-channel design in a single module

• 100% increase in port density

• Reduced chassis space consumption

• Lower overall power consumption

• Reduced capital expenditure (CAPEX)

For OLT equipment, access switches, and high-density optical access platforms, CSFP significantly improves resource utilization efficiency.

3. C-LIGHT 2.5G CSFP 20km Product Overview

https://www.c-light.com/products/details/1.25G_CSFP.html

The C-LIGHT 2.5G CSFP 20km bidirectional optical module is designed for telecom access networks, industrial optical communications, and enterprise fiber networks.

Key Specifications

4. Optical Performance Advantages of 2.5G CSFP 20km

High-Stability Transmission Performance

• Wavelength: 1490nm

• Transmit power: -6 dBm to 0 dBm

• Extinction ratio: ≥8.2 dB

Ensures stable signal quality over long-distance transmission.

Excellent Receiver Sensitivity

• Receive wavelength range: 1260–1360nm

• Receiver sensitivity: ≤ -24 dBm

• Saturation power: +1 dBm

Maintains stable communication even in complex link environments.

20km Long-Distance Coverage

Supports up to 20km transmission over single-mode fiber, suitable for campus networks, metro access networks, and telecom access deployments.

5. Typical Application Scenarios of 2.5G CSFP

FTTH Fiber-to-the-Home Networks

In GPON, EPON, and metro access networks, CSFP significantly improves OLT port utilization and enables more user connections.

Industrial Communication Systems

Industrial environments require wide-temperature operation. C-LIGHT industrial-grade versions support -40°C to +85°C, making them suitable for rail transit, power systems, and industrial automation.

Enterprise Campus Fiber Interconnects

For building interconnection, data aggregation, and backbone links, 20km transmission distance meets most deployment requirements.

Telecom Metro Access Networks

With dual-channel CSFP design, operators can achieve higher subscriber density within limited chassis space.

6. Why Choose C-LIGHT 2.5G CSFP 20km?

Higher Interface Density

Dual-channel design doubles port utilization compared to traditional SFP modules.

Carrier-Grade Reliability

• Telcordia GR-253 compliant

• IEC 60825 Class 1 laser safety standard

• RoHS compliant

• Strong EMI/ESD protection

Intelligent DDM Monitoring

Real-time monitoring of:

• Transmit optical power

• Receive optical power

• Temperature

• Voltage

• Module status

This improves operational efficiency and reduces total cost of ownership (TCO), allowing network upgrades without replacing existing platforms, helping operators reduce both CAPEX and OPEX.

7. Future Development Trends

With continuous evolution toward 10G, 25G, and higher-speed optical modules, CSFP technology will remain widely used in FTTH access networks, industrial communication systems, and small-to-medium operator networks.

C-LIGHT will continue to develop 25G and 10G CSFP optical modules.

Due to its high density, low cost, and mature reliability, CSFP technology will remain a key solution in access network deployments for the foreseeable future.

For users seeking higher port density and improved ROI, the C-LIGHT 2.5G CSFP 20km bidirectional optical module remains a highly cost-effective solution.

8. Frequently Asked Questions (FAQ)