DIRECT ANSWER / 01
Confirm equipment and mating parts before freezing cable configuration
A polarization-maintaining (PM) assembly is specified by more than connector type and length. Procurement also needs the operating wavelength, fibre type, connector key and slow-axis orientation, insertion loss, and extinction-ratio (ER) acceptance conditions. Limits and test conditions from one product family should not be transferred to another.
Show the angular datum on the interface drawing. Specify fibre and wavelength, both connectors, key/slot, slow-axis orientation relative to the key, required ER, test wavelength, port definition and report fields. Mark unconfirmed targets as pending instead of copying another supplier’s catalogue values.
SELECTION MATRIX / 02
Purchasing decision matrix
| Item | Identify | Correct action | Avoid |
|---|---|---|---|
| Fibre and wavelength | PM fibre construction/reference, alignment wavelength and operating band | Confirm the part reference covers the actual application band | Writing only “PM fibre” |
| Axis and key | Slow axis relative to connector key, key/slot width and viewing direction | Define angular datum and tolerance on an end-face/interface drawing | Using “key up” without a defined viewing direction |
| Optical acceptance | ER, insertion loss, test wavelengths and methods | Agree conditions, minimum/maximum limits and report format | Treating a catalogue typical value as a project guarantee |
| Mechanics and delivery | Both connectors, length, jacket, routing and labels | Provide drawing, sample requirements and batch test records | Ignoring the installed routing of the assembly |
RFQ INPUTS / 03
Minimum inputs a supplier can verify
| Category | Required input or confirmation |
|---|---|
| Application | Laser/device reference, wavelength range, mating ends and environment |
| Angular definition | Slow axis to key, key/slot, end-face view and drawing tolerance |
| Limits and method | ER target, loss limit, wavelength, method, port A/B and report requirements |
| Assembly construction | PM fibre type, length/tolerance, jacket, both ends, labels and sample plan |
BUYER FAQ / 04
Purchasing FAQ
Can ER values be copied from a supplier catalogue?
No. Values are tied to a specific fibre, wavelength, connector and test condition. Define project limits and acceptance method, then obtain written feasibility confirmation.
Why show slow-axis orientation relative to the connector key?
A PM assembly needs an angular relationship between the optical axis and mechanical datum. Manufacturer data sheets identify key width and axis-to-key alignment separately; confirm the selected configuration.
Are key widths and slots universal?
No. Connector keys and mating sockets affect mechanical alignment. Provide exact connector and mating-part references and drawings.
What should the test report record?
At minimum: assembly and revision, test wavelength and method, ER and loss results, port/orientation definition, date and applicable acceptance criteria. Agree project-specific fields.
SOURCES / 05
Sources and applicability
Sources checked: 2026-09-24. This guide clarifies purchasing fields; it does not replace current equipment data sheets, full standards or the approved project drawing.