Fiber Optic Collimators

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The fiber's output diverges steeply; the collimator's lens, set one focal length from the fiber tip, converts it to a collimated beam that filters, isolators, switches and measurement optics can work with. Jingsheng's documented device lines include collimators among the optical communication devices in its company profile — listed with lasers, isolators and circulators — which places this product inside the manufacturer's optical communication field, one of its five documented application areas.

Because the collimator is an interface component, its specification is a matching exercise. The fiber type and connector are the mechanical half of that match; the wavelength goes with the lens design and coating; the required beam diameter and working distance go with the focal length. A collimator chosen on price alone, without those matches, is one source of 'mystery loss' in a fiber system — the beam is clipped, aberrated or simply the wrong size for the optics behind it. The fiber collimator selection guide works through the matching in order.

Specifying a Fiber Collimator

• Fiber and connector — single-mode or multimode fiber, and the connector or pigtail format at the rear.
• Wavelength — the operating band the lens and its coating are correct at.
• Beam diameter — the collimated beam size the rest of the system expects.
• Working distance — how far the parallel beam must travel before the next element or the receiving collimator.

State in the enquiry whether the collimator is for a free-space link — as one of a matched pair or singly — or as the front end of a filter or isolator assembly. Where the system also needs beam handling after collimation, the same catalogue covers beam expanders and the full filter family. Pricing and minimums for fiber collimators are confirmed per specification in the written quotation, because the configuration — fiber, connector, wavelength, focal length — is the price.

Frequently Asked Questions

What information does a collimator quotation need?

Fiber type, connector, wavelength, required beam diameter and working distance. Those five items are the inputs the enquiry asks for.

Can collimators be supplied as a matched pair?

That must be confirmed in the enquiry: the source record does not document matched-pair supply or pair acceptance testing. If your link needs both ends specified together, state the link distance and ask for matched-pair availability and the coupling acceptance conditions to be confirmed in the written quotation.

Which applications use fiber collimators?

Optical communication systems, fiber lasers, sensing and test instruments — anywhere a fiber meets free-space optics.

Pairs, Links and the Free-Space Budget

The budget behind a collimator purchase is the free-space link budget, and it is worth stating plainly. A collimated beam diverges slowly but surely, so the fraction of light the receiving collimator captures falls with distance and rises with beam diameter; doubling the beam diameter roughly halves the divergence — it is the Rayleigh range that grows with the square of the beam radius — and that transforms what a metre of free space does to the coupling. This is why collimators for short bench links and collimators for room-scale links are different parts despite sharing a name, and why the working distance in the enquiry is not a formality. It is also why the receiving end should be specified in the same conversation: the pair is chosen together, with each end's beam stated against the other, instead of two independently chosen 'standard' parts. If the link also carries a filter, an isolator or a beam sampler in its free-space section, list them — their apertures are part of the same budget, and the collimator beam should be sized for the smallest of them.