PM Multi Fiber Collimator Supplier: Match Channel Count to the Optical Module Instead of Stocking One Generic Part

A PM multi fiber collimator supplier should help a buyer separate channel count from optical performance. Feiyi lists polarization-maintaining collimators with four, five, nine and sixteen fibers, all intended for compact multi-channel optical interfaces but not identical in polarization specification. The four- and five-fiber products list a minimum extinction ratio of 20 dB at 23 °C, the nine-fiber version lists 18 dB, and the sixteen-fiber version lists 17 dB. Treating them as one family with only a different fiber count can hide a requirement that matters to the actual instrument.

For a distributor, OEM or engineering buyer, the first step is to map the number of active optical channels, the wavelength of each channel, the polarization requirement and the physical space available in the module. Feiyi’s multi-fiber collimator pages share useful common characteristics—630 to 1550 nm wavelength options, typical insertion loss of 0.2 dB, maximum insertion loss of 0.25 dB, return loss of 60 dB, beam diameter below 0.5 mm and 300 mW maximum power handling—but the channel architecture still needs its own controlled item.

Four fibers are appropriate when the module has four defined optical paths, not when more capacity only sounds safer

Feiyi’s PM Four Fibers Collimator provides a compact route for four polarization-maintaining channels. A buyer should use it when the module drawing actually contains four paths that need to share a collimator package. If the system needs only two paths, the PM Dual Fiber Collimator is a more direct architecture. Adding unused fibers for future use can make labeling, routing and incoming inspection harder without creating value.

The four-fiber page lists a minimum extinction ratio of 20 dB at 23 °C and package options around 2.78×8 and 3.2×9 mm. Those values should remain attached to the four-channel configuration in the customer’s BOM.

A four-channel instrument should preserve the fiber-to-function map before assembly

Label the four fibers by function—such as transmit path, reference path, return path and monitor path—rather than by color alone. If the pigtails are similar, the functional map is what prevents a correct collimator from being connected incorrectly during module build.

Five fibers can be useful when one channel has a distinct reference or monitoring job

The PM Five Fibers Collimator is not simply a four-fiber device with a spare lead. In some instruments the fifth channel may be a reference, monitor or additional signal route. The procurement drawing should state why it exists. Feiyi lists the same broad wavelength family and 0.2 dB typical / 0.25 dB maximum insertion-loss values, with a minimum extinction ratio of 20 dB at 23 °C.

For a distributor, the presence of five fibers is a strong reason to keep this item separate from four-fiber stock. A technician should not need to count pigtails after the component is pulled from inventory to discover which build was shipped.

Nine-fiber collimators move the design from a few routes into a denser channel map

Feiyi’s PM Nine Fibers Collimator lists a minimum extinction ratio of 18 dB at 23 °C. That is different from the 20 dB figure on the four- and five-fiber pages. If a customer needs a higher polarization requirement, the buyer should not assume that the same number carries automatically into the denser device.

A nine-channel design also makes identification more important. A paper note such as fiber 1-9 clockwise is not enough unless the mechanical viewing direction is defined. Put the channel numbering on the drawing relative to a body datum or assembly view.

Dense channel numbering should have one unambiguous viewing direction

When nine or more fibers are present, channel maps can be mirrored accidentally between drawings and assembly stations. Define whether the map is viewed from the fiber side, lens side or another mechanical reference. A supplier and customer should be able to compare the same channel number without mentally flipping the image.

Sixteen fibers require inventory discipline because polarization margin and channel identity both matter

The PM Sixteen Fibers Collimator lists a minimum extinction ratio of 17 dB at 23 °C. For a high-density module, that figure should be reviewed against the system requirement before the part is approved. The lower listed minimum compared with the four-, five- and nine-fiber versions is exactly why a distributor should not describe the whole family with one generic polarization specification.

Sixteen similar pigtails also create a practical receiving problem. If the channel identity is not preserved through labeling, drawing and assembly records, troubleshooting can consume far more time than the optical test itself.

The shared 630-to-1550 nm wavelength list still needs a specific fiber choice for each order

Across the PM multi-fiber products, Feiyi lists wavelengths including 630, 780, 850, 980, 1064, 1310 and 1550 nm and corresponding fiber families such as PM630, PM780, PM850, PM980, PM1060, PM1310 and PM1550. A supplier can therefore support multiple optical bands, but a customer’s item should identify one approved wavelength/fiber combination.

For a distributor serving several industries, this is a useful way to structure inventory. Separate stock by channel count first, then wavelength/fiber family, then lens/working-distance and termination. Do not merge items because the metal or glass body appears identical.

C-Lens and G-Lens choices should follow the free-space geometry, not the channel count

Feiyi’s ordering information includes C-Lens and G-Lens choices with configurable working distance. That decision should come from the distance to the next optical element and the required beam behavior. A sixteen-fiber module does not automatically need a different lens type simply because it has more channels; conversely, a four-fiber design may need a different working distance if its filter, mirror or detector is positioned farther away.

External multi-fiber collimator suppliers similarly separate lens choice, working distance, fiber type and connectorization. Their exact numbers are not Feiyi specifications, but the design principle is consistent: the optical gap and module geometry should drive the lens configuration.

Working distance belongs on the mechanical drawing with the optical reference plane

If the drawing only says 3 mm working distance without defining where the measurement begins and ends, the assembly team can still build two different geometries. Define the reference plane that matters to the module and the position of the facing optical element.

Typical 0.2 dB loss should be checked across the channels that the instrument actually uses

Feiyi lists typical insertion loss of 0.2 dB and maximum of 0.25 dB across these PM multi-fiber pages. In a dense component, the buyer should define whether every channel must be measured and whether the acceptance record needs a channel-by-channel result. A single average number may hide an outlying path.

For a prototype, it may be practical to test every channel in detail. For repeat production, the inspection plan should reflect the customer’s risk and the supplier’s agreed test method. The important point is that the channel map and the test record use the same numbering.

Return loss, PDL and directivity should remain separate acceptance items

The Feiyi pages list return loss at 60 dB, polarization dependent loss at no more than 0.15 dB and directivity at no more than 0.1 dB. These parameters describe different behaviors. A buyer should not combine them into a single optical-quality line because a problem in one metric may have a different cause and system effect.

For a polarization-sensitive module, the extinction-ratio requirement is especially important and should be kept beside the channel-count-specific product. The four-, five-, nine- and sixteen-fiber pages do not all list the same minimum ER, so the controlled record should use the correct value for the selected device.

300 mW should be treated as the listed family limit, not as permission to ignore channel power distribution

Feiyi lists maximum power handling of 300 mW. A multi-channel module should still document the expected power on each active fiber. If the design has one channel carrying most of the optical power while the others are weak monitor paths, the supplier should know that distribution. If the system needs substantially higher power, move the discussion to a purpose-built high-power collimator rather than assuming the multi-fiber component can be uprated by request.

One high-power channel can dominate the thermal risk in a multi-channel assembly

Total channel count does not tell the supplier how optical power is distributed. A sixteen-fiber unit with low power on every channel is a different thermal problem from a four-fiber unit with one dominant source. The order should state the real operating condition when power is relevant.

Channel-count changes should trigger a module review instead of an automatic substitution

If a project moves from four fibers to nine or sixteen, the change affects pigtail routing, channel identification, body handling and the listed minimum extinction ratio. Treat that as a design revision, not a purchasing substitution. The receiving fixture and assembly instructions may also need to change because there are more paths to identify and test.

Likewise, reducing from sixteen to nine fibers can simplify the module, but only if the removed channels are truly unnecessary. Purchasing should not decide that change based on stock availability alone.

Packaging and receiving should preserve the channel map before the part reaches the optical bench

A multi-fiber collimator can arrive optically correct and still create trouble if pigtails are tangled, labels are lost or the body reference is unclear. If the customer requires numbered leads, grouped pigtails or a specific orientation label, place that requirement in the purchase drawing. At receiving, verify channel labels and body reference before technicians separate or reroute the fibers.

This is particularly important for nine- and sixteen-fiber parts. Once a bundle has been rearranged during module assembly, reconstructing the original channel identity from appearance alone may be impossible.

A high-density build should decide whether every channel needs the same polarization margin

Some optical modules use all channels symmetrically; others include one or two reference or monitor paths with different performance needs. The buyer should decide whether a single extinction-ratio requirement applies to every channel or whether the system acceptance plan treats certain paths differently. Do not invent a per-channel specification that is not on the Feiyi page, but do make the system requirement visible so the supplier can confirm what is practical for the exact build.

This matters most when moving from four or five fibers into nine or sixteen fibers because the listed family minimum changes. A module designer who needs more polarization margin than the standard page shows should ask for confirmation before freezing the drawing rather than assuming the lower-density value is available on the denser part.

Channel maps and optical test records should use the same numbering convention

If a test report calls a path Channel 7 while the assembly drawing calls the same lead Fiber 8, later troubleshooting becomes unnecessarily difficult. Use one numbering scheme from supplier drawing through incoming inspection and module test.

Body size and pigtail routing should be reviewed together in a dense optical module

Feiyi’s four-, five-, nine- and sixteen-fiber products use compact body dimensions in the roughly 2.78×8 to 3.2×9 mm range shown on the product pages. A dense module designer should check not only whether the body fits the bore or holder, but also whether the growing number of pigtails can leave the body without sharp bends or interference with neighboring parts.

The same external diameter can feel very different in assembly when four versus sixteen fibers must be dressed. Put the pigtail exit direction, minimum service loop and neighboring hardware on the mechanical drawing before the supplier build is frozen.

A distributor should stock by optical identity, not by a generic PM multi-fiber collimator description

A practical stock record should preserve at least the fiber count, wavelength/fiber family, lens type, working distance, axis convention, body size and pigtail or connector configuration. Then retain the channel map supplied to the customer. This prevents a four-fiber 1550 nm item from being treated as equivalent to a four-fiber 1064 nm item, and it prevents a sixteen-fiber part with a different listed ER from being substituted for a lower-density device.

Feiyi’s dual-fiber collimator article covers the two-path case. The multi-fiber family needs a different discipline: preserve the channel map and the performance values associated with the exact channel count. That is what makes repeat stocking useful to engineering rather than merely convenient for the warehouse.

Repeat orders should preserve the channel map together with lens and wavelength choices

Once a multi-fiber collimator has passed system test, save the exact channel count, wavelength and PM fiber family, lens type, working distance, axis convention, body size, pigtail construction, connector choice and the channel-numbering drawing. For nine- and sixteen-fiber versions, keep the approved extinction-ratio requirement with that specific item rather than carrying over a value from a lower-density product.

A replacement order described only as multi-fiber PM collimator forces the next engineer to reconstruct decisions that were already made. A reproducible record should let the supplier, buyer and assembly technician identify the same channels and optical interface without reopening the prototype notebook.