40GBASE-ER4 QSFP+ Module 1310nm 40km LC - Low Power 40G

In this review the QSFPTEK 40GBASE-ER4 QSFP+ module is evaluated for network engineers and data center operators who need reliable long-reach 40G links. The bottom line: this QSFP+ transceiver delivers the expected 40 Gbps aggregate bandwidth with LC duplex connectors and digital diagnostics monitoring, making it a practical choice for Campus Network and Data Center use where compatibility and low power matter. Our review finds it especially useful when interoperability with multiple vendors and conservative power budgets are priorities.

Key Features

• 40 Gbps rate: Provides four 10 Gbps lanes aggregated to 40 Gbps so high-throughput links are supported without changing existing QSFP+ ports.
• 1310 nm 40 km reach: Designed for single-mode fiber runs up to 40 km to connect remote buildings or long-haul campus links.
• DDM support: Built-in digital diagnostics monitoring delivers real-time operating parameters for easier fault finding and link management.
• Low power consumption: Draws under 3.5W so it is suitable for dense port count switches and reduces heat load in racks.
• Vendor compatibility: Market-tested to work with over 200 vendor devices and is QSFP+ MSA compliant for broad interoperability.

Who It's For

The module is best for network administrators running 40G aggregation or core links in campus networks and data centers who need a cost-effective, standards-compliant transceiver with monitoring. It fits environments where long single-mode fiber spans are required and where modest power consumption helps manage thermal budgets.

It is less appropriate for users who require shorter multimode links, non-LC connectors, or specialized vendor-locked optics with proprietary features. Buyers needing built-in switching or routing functionality should look at active equipment rather than a passive transceiver module.

Pros & Cons

Pros

• Supports full 40G bandwidth through a quad 10G lane QSFP+ interface for high-throughput links.
• Long reach of up to 40 km on single-mode fiber at 1310 nm for campus or metro use.
• DDM provides visibility into module status and link health for easier troubleshooting.
• Low power usage under 3.5W reduces rack heat and operating cost in dense deployments.

Cons

• Not intended for multimode fiber runs or short-range applications where SR optics would be more appropriate.

Specifications

Form Factor	QSFP+
Data Rate	40G (4x10G)
Wavelength	1310 nm
Maximum Reach	40 km on SMF
Connector	Duplex LC
Diagnostics	DDM / DOM supported
Power Consumption	<3.5W

Our Verdict

The QSFPTEK 40GBASE-ER4 QSFP+ module is a solid, standards-compliant option for organizations that need reliable 40G long-reach links with low power draw and diagnostic visibility. It represents good value for campus and data center deployments where interoperability across many vendors is required and a 40 km single-mode span is needed.

Frequently Asked Questions

Will this module work in third-party switches?
This transceiver is built to QSFP+ MSA and has been tested for compatibility with a wide range of vendors, so it will work in many third-party switches that accept standards-compliant optics.

What fiber type and connector are required?
Use OS2 single-mode fiber with duplex LC connectors for the 1310 nm, 40 km reach specified by the module.

Does it support real-time monitoring?
Yes, the module supports DDM/DOM, allowing monitoring of parameters like optical power and temperature for operational diagnostics.