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Fiber Optic Rotary Joints with 2 to 4 Channels

Only 25 mm to 28 mm Outer Housing Diameter

The smallest of the multichannel fiber optic rotary joint’s (FORJ) made by SPINNER is the type x.25 with an outer housing diameter of 25 mm and two to four channels. Precisely produced mechanical components, highly trained technicians, and active alignment of all optical parts combine to endow this FORJ with superior performance and reliability in a compact case.

As the only manufacturer worldwide, we offer fiber optic rotary joints with straight, L- und U-shaped outputs, available for single or multi-channel configurations.

Type x.25 FORJ - Straight Version

The two, three or four channels can be separately specified according to your needs. This ensures that the FORJ is optimally suited to the application at hand. For example, it is possible to have both single-mode and multimode channels on the same FORJ, thus providing a high degree of flexibility in all situations. Thanks to SPINNER’s proprietary alignment technology, the optical parameters of the channels can also be individually specified for optimal performance.

The mechanical components can also be adjusted to meet your needs. At a lower ingress protection level of IP50, high rotational speeds up to 6000 rpm are possible, while IP65 is for difficult environmental conditions.

To facilitate installation and minimize the effect on your system, SPINNER provides customized FLEXIFLANGES.

If space is limited but more bandwidth is required, you can add virtual channels by combining our x.25 types with a WDM (wavelength division multiplexing) setup – both DWDM and CWDM. This configuration enables the transmission of multiple independent channels over a single fiber, maximizing performance without increasing system size.

Specifications x.25

Channel count: 2 – 4
Fiber types: single-mode (SM), multimode (MM)
Max. insertion loss: standard 3.5 dB, premium 2.0 dB
Insertion loss variation over rotation max: standard 1.5 dB, premium 1.0 dB
Return loss: 50 dB
Wavelength: 400 nm –1600 nm (depending on fiber type)
Rotational speed: up to 6,000 rpm
Weight (excl. connectors): 250 g
Torque: 0.8 Nm
Degree of protection: IP50, IP65
Recommended temperature range: -40 °C to +85 °C

Applications

Type x.25 FORJ - L Form

An absolute novelty and exclusively available from SPINNER is the L-shaped x.25. In this design, the fibers on the stator side exit the FORJ at a 90° angle to its rotational axis, thus leaving plenty of room at the top for additional instrumentation.

This concept combines a small diameter with a short length, making it ideally suited for use in 4K or 8K cameras, for example.

Technical Data x.25L

Channel count: 2 – 4
Fiber types: single-mode (SM), multimode (MM)
insertion loss: standard 4.0 dB, premium 2.5 dB
Insertion loss variation over rotation max: standard 1.5 dB, premium 1.0 dB
Return loss: 50 dB
Wavelength: 400 nm – 1600 nm (depending on fiber type)
Rotational speed: up to 6,000 rpm
Weight (excl. connectors): 250 g
Torque: 0.8 Nm
Degree of protection: IP50, IP65
Recommended temperature range: -40 °C to +85 °C

Applications

4K or 8K camera systems, gimbals and whenever space is at a premium

Type x.25 FORJ - U Form

The Optical Rotary Joint 2.25U stands out with its unique design: both fiber optic outputs are positioned at a 90° angle to the rotation axis. Thanks to high-precision manufacturing and premium optical components, it ensures outstanding reliability and long service life.

The 2.25U is particularly well-suited for high-speed data signals with Tx and Rx channels in space-limited applications – such as opposing circuit boards or articulated joints – where compactness and performance are equally crucial.

Specifications x.25U

Channel count: 2 – 4
Fiber types: single-mode (SM), multimode (MM)
Max. insertion loss: 4.5 dB
Insertion loss variation over rotation max: 1.5 dB
Return loss: 50 dB (SM), 35 dB (MM)
Wavelength: 400 nm –1600 nm (depending on fiber type)
Rotational speed: up to 3,000 rpm
Weight (excl. connectors): 250 g
Torque: 0.01 Nm
Degree of protection: IP50, IP65
Recommended temperature range: -40 °C to +85 °C

Applications

Medical | Winch Systems | Surveillance Gimbals | Low-profile Applications | Camera Applications

Type 4.25 FORJ - T-Type

In this innovative design, the fibers exit the stator side of the FORJ at a 90° angle to the rotation axis, creating valuable space above the rotary joint for additional instrumentation or sensors.

While in two-channel versions, both fibers exit in the same direction (L-Type), the four-channel variants use a T-Type configuration, where two fibers exit in opposite directions.
This concept combines a small outer diameter with a short overall length, making it ideal for space-constrained applications such as 4K and 8K cameras or optronic systems.

The design is particularly attractive when combined with a compact slip ring for power and signal transmission, enabling fully integrated electro-optical systems.

Technical Data x.25L

Channel count: 2 – 4
Fiber types: single-mode (SM), multimode (MM)
insertion loss: standard 4.0 dB, premium 2.5 dB
Insertion loss variation over rotation max: standard 1.5 dB, premium 1.0 dB
Return loss: 50 dB
Wavelength: 400 nm – 1600 nm (depending on fiber type)
Rotational speed: up to 6,000 rpm
Weight (excl. connectors): 250 g
Torque: 0.8 Nm
Degree of protection: IP50, IP65
Recommended temperature range: -40 °C to +85 °C

Applications

Medical Technology | Winch Systems | Surveillance Gimbals | Low-profile Applications | Aviation

FORJ 2.28 and 2.28HS (High Speed)

The 2.28 fiber optic rotary joint (FORJ) with an outer diameter of 28 mm is a key component for high-performance applications where data and signal transmission across rotating interfaces was previously difficult or even impossible.

The 2.28 series is available in two configurations:

The singlemode version with two singlemode channels is designed for industrial and sensing applications.

The mixed version, developed for medical use, enables in vivo imaging with rotating catheters – for example in intravascular optical coherence tomography (OCT).

The mixed version allows the combination of different fiber types, typically a singlemode channel with a multimode large-core fiber. This enables multimodal imaging, where a conventional OCT image is overlaid with fluorescence or spectroscopic data for enhanced visualization and analysis.

Designed for rotational speeds up to 12,000 rpm, the 2.28HS FORJ supports live imaging at frame rates up to 200 fps.
Its robust, high-precision mechanics ensure long-term reliability and consistent optical performance, even under dynamic operating conditions.

Combinations with an additional power transmission, a motor and/or an encoder are also available

Specifications 2.28 / 2.28 High Speed

Channel count: 4
Fiber types: single-mode (SM), multimode (MM), large core fiber (LCF)
Max. insertion loss: standard 3.5 dB
Insertion loss variation over rotation max: standard 1.5 dB
Return loss: 50 dB (SM), 35 dB (MM)
Wavelength: 400 nm –1600 nm (depending on fiber type)
Rotational speed: up to 12,000 rpm
Weight (excl. connectors): < 250 g
Torque: 0.01 Nm
Degree of protection: IP54
Recommended temperature range: typically room temperature

Applications

Medical Technology | Sensoric Systems

Fiber Optics - From Single Channel up to 109 Channels!

Single Channel Fiber Optics

Ø 6,8 mm/14 mm/17 mm
(Type 1.068/1.14/1.17)

The single-channel fiber-optic rotary couplings of SPINNER feature maximum performance in a minimum of space. It comes in three different standard versions as well as customized solutions.

2 to 4 Channel Fiber Optics

Ø 25 mm (Type x.25)

The mechanical design of the FORJ x.25, which is available with 2, 3 or 4 channels, makes this fibre optic rotary joint very compact. Also available as L-form!

3 to 8 Channel Fiber Optics

Ø 40 mm (Type x.40)

The SPINNER FORJ x.40 delivers market-leading compactness for multi-channel solutions with up to eight channels, with an outer housing diameter of only 39.5 mm.

7 to 109 Channel Fiber Optics

Ø 60 mm (Type x.60)

Ideal for multi-channel applications. These rotary joints cover the full range from seven up to 109 channels.

Pressure Compensated - Subsea Type

Ø 17 mm/65 mm
(Type 1.17pc/x.65pc)

The pressure compensated FORJs are designed for the use in deepsea and withstands brutal vibrations, high humidity, and seawater.

Large Core Fiber Optic

For special applications, e.g. life sciences and medical technology, SPINNER supplies fiber optic rotary joints with large core fibers or plastic optical fibers.