To select a 100G QSFP28 optical transceiver, first match its transmission distance and fiber type to your link, then confirm the connector, wavelength, host-device compatibility, and link configuration. Common choices include SR4 for short-reach multimode fiber, LR4 or CWDM4 for duplex single-mode links, and PSM4 for parallel single-mode fiber. A module’s QSFP28 form factor alone does not guarantee that it will work in every switch or router, so verify the exact equipment and deployment requirements before ordering.
This guide is for network engineers, data-center operators, system integrators, and procurement teams sourcing 100G QSFP28 modules for new deployments or replacements. It is useful when comparing optical types, checking interoperability, or preparing a request for quotation. The goal is to help you create a clear, testable specification rather than select a module based on speed and form factor alone.
A QSFP28 transceiver converts electrical signals from a network device into optical signals for transmission over fiber, then converts received optical signals back into electrical signals. The “100G” designation refers to a nominal 100-gigabit-per-second network interface, while QSFP28 identifies the module’s form factor and electrical interface family. The optical implementation, reach, fiber, and connector depend on the specific module type.
In a typical link, one transceiver is installed at each endpoint and connected through a compatible fiber plant. The two ends must use compatible optical standards and link configurations, even if their manufacturer labels differ. For a complete design, also account for patch panels, intermediate connections, and any planned breakout from 100GbE to lower-speed ports.
Different 100G QSFP28 types address different distances and fiber infrastructures. The figures below are common reference limits for recognized module types; actual supported reach can depend on the module specification, fiber grade, connector quality, and link-loss budget. Confirm the datasheet for the specific part number before finalizing a design.
| Type | Fiber and connector | Typical reference reach | Common fit |
|---|---|---|---|
| 100GBASE-SR4 | Multimode fiber; MPO/MTP-style interface | Up to 70 m on OM3 or 100 m on OM4 | Short-reach data-center links |
| 100GBASE-LR4 | Single-mode fiber; duplex LC | Up to 10 km | Longer campus or data-center connections |
| 100G CWDM4 | Single-mode fiber; duplex LC | Commonly specified up to 2 km | Data-center links where duplex fiber is preferred |
| 100G PSM4 | Single-mode parallel fiber; MPO/MTP-style interface | Commonly specified up to 500 m | Parallel-fiber links over single-mode infrastructure |
SR4 uses parallel optical lanes and is designed for short links over multimode fiber. Its MPO-style connector and fiber polarity require attention during installation, especially when patch panels or trunk cables are part of the path. Choose SR4 when the existing multimode plant supports the required distance and the parallel-fiber connection is practical.
LR4 and CWDM4 carry 100G over duplex single-mode fiber using multiple optical wavelengths. Both commonly use LC connectors, but they differ in optical specifications and intended reach, so they should not be treated as interchangeable. Check the module’s standard or MSA designation, supported distance, wavelength details, and endpoint requirements against the equipment documentation.
PSM4 uses parallel optical paths over single-mode fiber and typically connects through an MPO-style interface. It can suit links where parallel cabling is available and the target distance is within the module’s specified range. Before selecting it, compare the cost and layout of the required fiber plant with a duplex-fiber alternative.
For connections within a rack or between nearby racks, compare the planned distance with the reach of an SR4 module and the installed multimode fiber grade. For links between equipment rooms or across a larger facility, a single-mode option such as CWDM4 or LR4 may be more appropriate, depending on distance and infrastructure. PSM4 is worth evaluating where parallel single-mode cabling is already part of the design.
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Do not use reach alone as the selection rule. Connector type, fiber routing, patch-panel losses, polarity, and the number of fiber strands available can determine whether a nominally suitable module will work in the real link. If the connection is a switch-to-server or switch-to-switch link, also confirm that both devices support the chosen line rate and optical mode.
Compatibility can depend on the host device’s transceiver policy, firmware, and port configuration. Some platforms accept modules from multiple suppliers, while others may apply specific coding or validation requirements. Provide the exact equipment model and software context to your supplier rather than requesting a generic “compatible 100G module.”
Confirm the connector at both ends and the type of cable needed between them. MPO-based parallel links require correct polarity and lane mapping, while duplex LC links require the transmit and receive paths to connect correctly. A mismatch in fiber type or connector arrangement can prevent a link from coming up even when the transceivers themselves are appropriate.
Check the device’s supported module power and thermal envelope against the transceiver datasheet. Operating temperature ranges and power consumption vary by model, so use the values for the exact part number rather than relying on a category average. If operations staff depend on digital diagnostics, confirm which monitoring parameters the module exposes and how the host reads them.
Pricing is affected by the optical type, reach, host compatibility requirements, diagnostics, and order quantity. A short-reach multimode module and a longer-reach single-mode module are not directly comparable on price because their optical designs and deployment requirements differ. For an accurate quotation, provide the target specification, quantity, destination, and whether samples or qualification units are needed.
Minimum order quantities and lead times can vary with stock status, configuration, and production planning. Ask the supplier to identify the quoted part number, availability basis, shipping terms, and any applicable sample or production schedule. For repeat purchasing, align the approved specification and labeling requirements before placing the initial order.
A supplier should be able to help translate the link design into a precise module specification and explain any assumptions. Ask for a datasheet, compatibility information relevant to your host, and clarification of the module’s optical standard, reach, connector, and operating range. If your project uses an unusual host or cabling layout, share those details early so the proposed solution can be reviewed against the actual deployment.
The right 100G QSFP28 optical transceiver is the one that matches the complete link: endpoint equipment, distance, fiber infrastructure, connector, and operational requirements. Start by documenting those details, shortlist the optical type that fits, and confirm compatibility at both ends before committing to a production order. This process helps prevent common mismatches such as choosing the wrong fiber interface or assuming all QSFP28 modules are interchangeable.
OPTEKCOM supports B2B buyers evaluating optical transceivers and interconnect options for network projects. Share your device models, link distance, fiber type, connector preference, quantity, and destination to request a specification review and quotation. Where a detail is not yet confirmed, state the uncertainty so the proposed configuration can be checked before procurement.
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