Juniper Networks QDD-400G-VSR4 Compatible 400G QSFP-DD SR4 Transceiver Module

Built for hosts recognizing QDD-400G-VSR4, this HT-manufactured QSFP-DD module delivers 400G transmission at 850nm. Its rated reach is 30m on OM3 / 50m on OM4, with MPO-12/APC as the physical interface. The specifications and engineering guidance below support structured fiber installations preserve a documented and serviceable optical channel, while keeping HT manufacture separate from the OEM cross-reference.
OEM Part Number: QDD-400G-VSR4HT Part Number: QDD-400G-VSR4
Product Highlights
- Compatible alternative to Juniper Networks QDD-400G-VSR4
- 400G connectivity at 400Gbps
- Optical wavelength: 850nm
- Specified reach: 30m on OM3 / 50m on OM4
- MPO-12/APC / MMF interface
- Digital diagnostic monitoring: Supported
- Operating temperature: 0 to 70°C (32 to 158°F)
Specifications
| Juniper Networks Compatible | QDD-400G-VSR4 |
|---|---|
| Manufacturer | HT |
| HT Part Number | QDD-400G-VSR4 |
| Form Factor | QSFP-DD |
| Max. Data Rate | 400Gbps |
| Wavelength | 850nm |
| Max. Cable Distance | 30m@OM3/50m@OM4 |
| Connector | MPO-12/APC |
| Media | MMF |
| Transmitter Type | VCSEL 850nm |
| Receiver Type | PIN |
| TX Power | -4.6~4dBm |
| Minimum Receiver Power | -6.4dBm |
| Power Budget | 1.8dB |
| Receiver Overload | 4dBm |
| Max. Power Consumption | 8W |
| Extinction Ratio | 2.5dB |
| DDM/DOM | Supported |
| Commercial Temperature Range | 0 to 70°C (32 to 158°F) |
| Modulation (Electrical) | 8x50Gbps-PAM4 |
| Modulation (Optical) | 4x100Gbps-PAM4 |
| DSP | TX and RX |
| Inbuilt FEC | Support |
| Core Size | 50/125µm |
| Packaging Technology | COB |
| MTBF | 1410258 Hours (@40°C, 90% CL) |
| Application | 400G Ethernet |
| Protocols | QSFP-DD MSA, CMIS Rev5.0, IEEE 802.3df-2024 |
Applications and Optical Link Design
Typical deployments include switch-to-switch, switch-to-server and aggregation links inside a data hall or between adjacent equipment rooms. The MPO-12/APC interface connects to the specified multimode cabling, and the stated reach depends on fiber grade and link loss. Keep this interface on the matching multimode optical standard rather than connecting it directly to a single-mode wavelength or reach variant.
Before deployment, check the host port type, supported data rate and firmware requirements. The 400G interface configuration must match the remote equipment; sharing a QSFP-DD housing alone does not make two transceiver types interoperable.
The multimode channel should use the fiber grade associated with the stated 30m on OM3 / 50m on OM4 reach. Keep the MPO-12/APC end faces clean and avoid tight bends. Different multimode standards are not interchangeable merely because they share a connector.
Juniper Networks Compatibility and Factory Testing
Compatibility testing for QDD-400G-VSR4 combines identification with a live link and available transmit, receive and alarm information. Connector condition is inspected separately. Equipment model, hardware revision and software release can be reviewed before dispatch where platform behavior is uncertain.
Optical Acceptance, Diagnostics and Handling
For this model, the specified transmit-power range is -4.6~4dBm; the stated optical power budget is 1.8dB. A sound acceptance record includes link state, diagnostic temperature, supply voltage and transmit or receive levels where the host exposes them. Compare the readings with the stated ranges rather than treating any received light as proof of adequate margin. Persistent alarms or borderline values should trigger an end-face and complete-channel inspection. Diagnostic monitoring is listed as Supported. Before every insertion, keep dust caps in place until the patch lead is ready, avoid touching the optical end face and use an appropriate inspection and cleaning procedure. Do not look into an active optical interface.
Structured Fiber Pathways and Serviceability
Treat the transceiver as part of the complete channel. Follow the intended patch-panel route, maintain bend control and leave service access around the port. Confirm connector polish and fiber type at every mated pair; a documented service allowance is preferable to excess slack concealed inside a rack. For this model, the principal parameters are data rate 400Gbps, wavelength 850nm, rated reach 30m on OM3 / 50m on OM4.
Ordering Information
Use QDD-400G-VSR4 as the compatibility cross-reference and QDD-400G-VSR4 as the HT ordering identity. Keep other reaches or wavelength directions on separate order lines. Neutral labels, customer packaging and project-specific compatibility review are available on request.
Shipping and Lead Time
Standard configurations normally ship within one to three working days, with production lead times confirmed for larger quantities. International courier, air freight and sea freight are available; customer courier accounts and nominated forwarders are accepted.
Quality Assurance and Packaging
Before packing, the module receives interface inspection, identification and link checks. Protective packaging avoids pressure on the connector and latch. Customer references, rack groups and project packing lists can be added for volume orders.
Frequently Asked Questions
Is this an original Juniper Networks transceiver?
No. It is an HT-manufactured compatible alternative for equipment that specifies QDD-400G-VSR4, not an original Juniper Networks-branded module.
Which fiber and connector are required?
Use MPO-12/APC with MMF. The specified maximum reach is 30m on OM3 / 50m on OM4, subject to fiber quality and total link loss.
Can it be mixed with another wavelength or reach version?
Only when the two ends share the same optical standard, wavelength plan and supported data rate. Check the exact part numbers and link budget rather than relying only on the module form factor.
QDD-400G-VSR4