100G Module Selection: Form Factors and Reaches

The 100G form factor question

The first 100G question is the host port, because the form factor is decided by the port rather than by preference. Most 100G host ports accept QSFP28 modules, and the 100G product page on this site is a QSFP28 module. A host with a different 100G port type needs a different form factor, and no form factor adapter changes the underlying lane configuration: a module that does not match the port does not work, regardless of its rate or optical figures.

Within QSFP28, the second question is the optical line: single-mode or multimode, and within single-mode, which reach. The product page on this site is a single-mode CWDM4 module at up to 2km, which covers campus and data center links in that range. Multimode 100G lines and longer single-mode 100G lines are guide-level only on this site, because no module in those lines carries a listed specification here, and their figures must be confirmed per model in an enquiry.

Reach within 100G single-mode

Single-mode 100G reach divides into shorter lines for data center and campus links and longer lines for metro and inter-site links, and the boundary between them is drawn by the measured link length rather than by the rate. A link within the shorter range does not need a longer-reach module, and a link beyond it cannot use a shorter-reach module, so the measured length is the deciding figure. Loss budget runs alongside reach: a link within the reach figure but with excessive connector loss can still fall outside the design budget.

The CWDM4 module on this site illustrates the shorter single-mode range, with its listed distance including a channel insertion loss budget. That pairing of distance and loss budget is the correct way to read any 100G reach figure, and a buyer who reads distance without loss budget is reading half a specification. State both the length and the connector count in the enquiry when the loss budget is tight.

Host requirements for 100G

Host requirements for 100G modules go beyond the port type. Forward error correction support, lane configuration and power budget all need to match between host and module, and a mismatch in any of them fails the link even when the optical figures fit. The CWDM4 product page on this site states its host forward error correction requirement explicitly, and that requirement should be checked against the host before ordering rather than discovered at installation.

Power is the host requirement most often overlooked at 100G, because 100G modules draw materially more power than 10G modules and the host port must supply and cool that power. The product page flags a power figure conflict for its own module, which is a reminder to confirm power per model in the enquiry rather than assuming a standard figure. A host that cannot supply the confirmed power for the confirmed module cannot use that module, whatever its optical figures.

What to send in a 100G enquiry

A complete 100G enquiry names the host port type, the fibre type, the measured link length including patch cords, the connector count for loss estimation, the host platform and its forward error correction support, the quantity and the environment. Each item removes a round of questions, and together they usually allow a quotation, a compatibility confirmation and a power check without further correspondence. An enquiry that names only the rate will need at least one further round, because none of the other items can be inferred from the rate alone.

Where the requirement spans several 100G lines, for example a mix of short multimode links and longer single-mode links in one refresh, send one enquiry covering the whole refresh rather than separate enquiries per line. A combined enquiry lets the supplier check the combination, including whether a single host platform serves all the lines, and it avoids the situation where each line is confirmed separately but the combination does not work together.

Before you send the enquiry

A good enquiry for any topic in this article names the rate, the wavelength, the fibre type, the distance, the connector, the quantity and the application, plus the host platform when compatibility matters and any certification document needed by name. Each item removes a round of questions, and together they usually allow a quotation and a compatibility confirmation without further correspondence. An enquiry that names only a rate, or only a module-style name, will need at least one further round, because none of the other items can be inferred from the rate alone.

Environment and quantity also belong in the first message. Quantity affects the quotation and the delivery schedule, and environment matters because the listed temperature range for a module covers ordinary indoor conditions; links in unconditioned spaces, in roof voids or in outdoor enclosures fall outside that range and should be raised explicitly. Stating the environment when it is not an ordinary indoor data center or wiring closet lets the temperature grade be confirmed as part of the order rather than discovered as a failure in summer or winter.

Finally, check whether the line you need has a product page on this site or only a guide page. A product page carries a listed specification for a specific model, and an enquiry against it can confirm price, stock and compatibility for that model. A guide page explains the line and routes you to an enquiry, because no listed specification exists for that line here. Knowing which of the two you are reading prevents the most common buying mistake on this site, which is treating a guide figure, a title figure or a standard figure as if it were a specification for a specific module.

Frequently asked questions

How do I get a quotation?

Send an enquiry naming the model, the rate, the wavelength, the distance and the quantity you need, plus the application. Quotations are confirmed per order, and specifications are confirmed per model before payment. This site does not list fixed selling figures, and no price is shown for any model.

What certification documents can you provide?

The company states ISO 9001, CE, FC, 3C and RoHS names. Certificates are available upon request. If a buyer needs a certificate for a specific model, name the model in the enquiry so the correct document can be checked. No certificate numbers are published on this site.

Do the specifications on one page apply to the whole range?

No. Specifications are shown per model and must not be read across the whole range. Where a value is not listed for a model, the page says to confirm per model rather than filling in a generic figure, and where the source pages disagree, the page flags the conflict instead of choosing one value as fact.

What are the minimum order quantity and lead time?

At company level both are unavailable on this site and are confirmed per model in the enquiry. A single-model note, where one exists, is marked as applying to that model only and must not be read as a company-wide term.