Product
40G QSFP+ ER4 Fiber Optic Transceiver Module 1310nm 40km LC SMF DDM
40G QSFP+ 1310nm 40km- Model reference
- QSFP+ER4
- Data rate
- 40G
- Wavelength
- 1310 nm
- Reach
- 40KM
- Form factor
- QSFP+
Key specifications
Original part-number references
These references compare optical specifications. Confirm the host device, firmware and coding profile before deployment.
| Brand | Original part number | Model reference | Optical specification reference | Next step |
|---|---|---|---|---|
| CISCO | QSFP-40G-ER4 | QSFP+ER4 | 40GBASE-ER4 QSFP+ transceiver, 1310 nm CWDM band, 40 km over SMF, duplex LC, with digital diagnostics. Cisco 40GBASE QSFP Modules Data SheetReviewed 2026-08-17 | Specification matchCheck host compatibility |
| ARISTA | QSFP-40G-ER4 | QSFP+ER4 | 40GBASE-ER4 QSFP+ transceiver, 1310 nm CWDM band, 40 km over SMF, duplex LC, with digital diagnostics. Arista Optics Modules and Cables Data SheetReviewed 2026-08-17 | Specification matchCheck host compatibility |
| JUNIPER | JNP-QSFP-40GE-ER4 | QSFP+ER4 | 40GBASE-ER4 QSFP+ transceiver, 1310 nm CWDM band, 40 km over SMF, duplex LC, with digital diagnostics. Juniper 40GBASE-ER4 Hardware Compatibility EntriesReviewed 2026-08-17 | Specification matchCheck host compatibility |
| JUNIPER | 740-066424 | QSFP+ER4 | 40GBASE-ER4 QSFP+ transceiver, 1310 nm CWDM band, 40 km over SMF, duplex LC, with digital diagnostics. Juniper 40GBASE-ER4 Hardware Compatibility EntriesReviewed 2026-08-17 | Specification matchCheck host compatibility |
| JUNIPER | QSFPP-40GBASE-ER4 | QSFP+ER4 | 40GBASE-ER4 QSFP+ transceiver, 1310 nm CWDM band, 40 km over SMF, duplex LC, with digital diagnostics. Juniper 40GBASE-ER4 Hardware Compatibility EntriesReviewed 2026-08-17 | Specification matchCheck host compatibility |
| JUNIPER | 740-059185 | QSFP+ER4 | 40GBASE-ER4 QSFP+ transceiver, 1310 nm CWDM band, 40 km over SMF, duplex LC, with digital diagnostics. Juniper 40GBASE-ER4 Hardware Compatibility EntriesReviewed 2026-08-17 | Specification matchCheck host compatibility |
Compatibility matching
Compatible with a wide range of major network brands.
Send the host device brand, model and link requirements so we can match an appropriate option.Applications
Review where this product fits the link design.
Confirm the host port, fibre or cable path, distance and operating environment before selecting the final variant.
- Endpoint fitHost device, port role and remote-end interface
- Link fitRate, reach, wavelength, fibre and connector
- Project fitEnvironment, quantity and document requirements
Testing evidence
Request evidence against the exact product scope.
Available evidence depends on the model and agreed review scope. Ask for the checks needed by engineering or procurement before approving a sample or rollout.
- Product identityModel, label, connector and wavelength details
- Host contextCoding or recognition evidence where applicable
- Output evidenceOptical, diagnostic or link information where available
Product datasheets
Review the document for the exact model.
Review the document for the exact model and reach before approving a sample or rollout.
Download QSFP+ER4 specification (PDF)Related questions
Five answers for this product path.
Product selectionHow can I identify the correct form factor?
Check the device manual and the marking on the existing module or cable. SFP, SFP+, SFP28, QSFP+, QSFP28, QSFP-DD and OSFP are not interchangeable merely because their connectors look similar.
Browse productsCompatibility & codingWill DOM or DDM readings be available on the host?
They are available only when the module, interface and host software support the diagnostic functions and expose them correctly. Confirm the required readings as part of the device review.
Start a model reviewOptical link designCan temperature influence optical margin?
Optical output, receiver performance and fibre or connector conditions can vary with environment. Use the specified operating range and retain reasonable link margin for the deployment.
Use the selection guideHigh-speed deploymentHow should I compare QSFP-DD and OSFP for 400G?
Start with the host port and supported interface list. The form factors have different mechanical and thermal characteristics and should not be treated as direct substitutes without device support.
Plan a technical reviewDocuments & procurementHow do I make sure a document applies to my exact model?
Compare the model reference, interface, reach and variant with your product shortlist. If the document is not published or the revision is unclear, send the model and required document type through the document request form before using it for approval.
Request a document pack