Fibre optic rotary joints
Princetel JXn series fibre optic rotary joint
Multi-channel fibre optic rotary joint with 2 to 19 channels, each single-mode or multimode, under 5 dB insertion loss (typically 2–3 dB), up to 200 rpm and up to IP65, in a 67 mm diameter body.
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What are you specifying?
Select everything you need. A motor, drive and gearbox can be specified together as one axis.
Key specifications
| Speed (max) | 200 rpm |
|---|---|
| Ingress protection | up to IP65 |
| Temperature | -40–75 °C |
| Fibre channels (max) | 19 |
| Rated life (revolutions) | 100 million (estimated) |
| Fibre | single-mode or multimode per channel |
| Wavelength | 1270–1610 (SM); 850 and 1310 (MM) |
| Insertion loss | <5 (typ. 2–3) |
| Size | 67 mm dia. x 122 mm |
Summarised in our own words from Princetel, Inc.'s published data; series maxima, individual models vary. Last checked 2026-10-30. Source 1
Specify Motion is not affiliated with Princetel, Inc.. Princetel and JXn series are used only to identify the product. Comparisons use published figures; always confirm against the current datasheet.
Princetel JXn series replacement and alternative options
Use these supply-network options as a starting point for an engineering check. We can also help source the original Princetel part. Published series figures do not establish an exact-model or drop-in replacement: confirm ratings, fit, interfaces and approvals for your application.
Fibre optic rotary joints that carry single-mode or multi-mode optical channels across rotation for high-bandwidth, interference-free data. Channel counts run from one to fifty.
| Published maximum | JXn series | FR Series Fiber Optic Rotary Joint |
|---|---|---|
| Speed | 200 rpm | 2,000 rpm meets or exceeds |
| Fibre channels | 19 | 50 meets or exceeds |
Hybrid units combining fibre optic channels with power and signal circuits, used on electro-optical pod systems.
| Published maximum | JXn series | Fiber Optic Integrated Electrical Slip… |
|---|---|---|
| Circuits | — | 70 |
| Current per circuit | — | 30 A |
| Speed | 200 rpm | 500 rpm meets or exceeds |
| Fibre channels | 19 | — |
Figures are the highest published for each series and are not always measured the same way. A higher figure is not automatically a better choice: mounting, duty cycle, feedback, connectors and approvals matter too. An engineer will check the fit against your application before recommending anything.
Typical applications
What a fibre optic rotary joint is
A fibre optic rotary joint, or FORJ, is the optical equivalent of a slip ring: it passes light signals between a fixed and a rotating fibre without a physical join. In a single-channel unit the two fibre ends sit on the rotation axis with collimating lenses so the beam crosses a small gap. Multi-channel units use a derotating optical element, such as a Dove prism, so several fibres can share the axis. Joints are built for single-mode or multimode fibre and can be combined with electrical slip rings.
When engineers choose a fibre optic rotary joint
Choose a FORJ when the rotating part needs very high bandwidth, immunity to electromagnetic interference or long transmission distances, as in subsea vehicles, cable reels, radar and video systems. It is passive and wear is very low because nothing touches. The trade-offs are insertion loss, which must fit the optical budget, sensitivity to contamination and a higher cost for multi-channel units. If data rates are modest and EMC is manageable, an electrical Ethernet slip ring may be simpler.
How to specify the Princetel JXn series
Send these with your enquiry and an engineer can confirm the right JXn series variant or an equivalent:
- Number of optical channels
- Fibre type: single-mode or multimode, core size (µm)
- Operating wavelengths (nm)
- Maximum insertion loss and loss variation during rotation (dB)
- Return loss requirement (dB)
- Connector type, such as FC, ST, LC or SC
- Speed (rpm), environment and any electrical circuits to combine
Common mistakes to avoid
- Not including the FORJ insertion loss in the full link optical budget
- Mixing single-mode and multimode fibres between the joint and the transceivers
- Leaving connectors uncapped during assembly, which contaminates the optical faces
- Specifying many channels when wavelength multiplexing would cut cost and size
Princetel JXn series: frequently asked questions
Can you help replace Princetel JXn series or source the original?
Send the full model code, quantity and required date. Our engineers can check original-part availability and assess suitable alternatives, including supply-network options where appropriate. We confirm compatibility and any changes needed before recommending a replacement.
What is the Princetel JXn series?
Multi-channel fibre optic rotary joint with 2 to 19 channels, each single-mode or multimode, under 5 dB insertion loss (typically 2–3 dB), up to 200 rpm and up to IP65, in a 67 mm diameter body. Published series figures include speed 200 rpm, temperature -40 °C, temperature 75 °C, fibre channels 19. It is made by Princetel, Inc.; Specify Motion can help source it or propose an equivalent.
Who makes the Princetel JXn series?
The Princetel JXn series is made by Princetel (Princetel, Inc.) and is listed here for engineers comparing options. Specify Motion is not affiliated with Princetel, Inc.; brand names are used only to identify the product.
What is the speed of the Princetel JXn series?
The published series maximum speed is 200 rpm. Individual models and sizes in the JXn series range vary, so check the exact variant against your duty cycle, mounting and environment, or ask our engineers to confirm the right size for you.
Is there an alternative to the Princetel JXn series?
We can assess suitable replacement options. On published figures, Motion Control Products FR Series Fiber Optic Rotary Joint and Motion Control Products Fiber Optic Integrated Electrical Slip Ring are options to assess from our supply network. An engineer confirms the fit against your application before recommending anything.
What is the difference between single-mode and multimode fibre optic rotary joints?
Single-mode joints carry light in one guided mode through a very small core, which suits long distances and high data rates but needs precise alignment. Multimode joints use a larger core, which is more tolerant of alignment and suits shorter links. The joint must match the fibre and transceivers already used in the system, so state the fibre type and wavelength.
Can a fibre optic rotary joint be combined with an electrical slip ring?
Yes. A common arrangement places the FORJ on the axis, with the electrical slip ring built around it in a through-bore format, so power and optical data pass through one assembly. This is widely used on cable reels, ROVs and radar. Specify the electrical circuits and optical channels together so the supplier can design one housing and sealing system.
Further reading: How to select a fibre optic rotary joint · How to select a slip ring · Slip rings
Other fibre optic rotary joints series
Engineer support
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Tell us how you use the Princetel JXn series: the load, speed, duty and environment. Our engineers will confirm whether it is still the right part, find it for you, or propose an alternative that fits better.
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How it works
From enquiry to delivery
Send a part number or describe the application. Our engineers take it from there: the right product, a clear quotation, and delivery and support arranged.
- 01Tell us what you needSend a part number, or configure the application, quantities and timing.
- 02An engineer reviews itWe check the specification and find the original part, a checked equivalent or a complete axis.
- 03Receive your quotationProducts, pricing, lead time and compatibility notes in one reply.
- 04Order and deliveryWhen you are happy, the order is placed and delivery and after-sales support are arranged.