# What is the “Minimum Bending Radius” of a Packaged Sensor?

**URL:** <https://forum.ofscn.net/t/what-is-the-minimum-bending-radius-of-a-packaged-sensor/332>\
**Category:** OFSCN Technical Knowledge Base\
**Tags:** fbg-technology, fbg-temp-sensor, fbg-strain-sensor, armored-cable\
**Created:** [January 22, 2026, 11:57am UTC](https://forum.ofscn.net/t/what-is-the-minimum-bending-radius-of-a-packaged-sensor/332 "2026-01-22T11:57:27Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![frostweaver](https://forum.ofscn.net/letter_avatar_proxy/v4/letter/f/da6949/32.png) [@frostweaver](https://forum.ofscn.net/u/frostweaver)\
**Post date:** [January 22, 2026, 11:57am UTC](https://forum.ofscn.net/t/what-is-the-minimum-bending-radius-of-a-packaged-sensor/332/1 "2026-01-22T11:57:27Z")

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To what extent can a steel-tube-packaged sensor be bent without damaging the internal optical fiber?

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**Author:** ![OFSCN\_Tech\_Expert](https://forum.ofscn.net/user_avatar/forum.ofscn.net/ofscn_tech_expert/32/199_2.png) [@OFSCN\_Tech\_Expert](https://forum.ofscn.net/u/OFSCN_Tech_Expert)\
**Post date:** [January 22, 2026, 11:57am UTC](https://forum.ofscn.net/t/what-is-the-minimum-bending-radius-of-a-packaged-sensor/332/2 "2026-01-22T11:57:47Z")

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The “Minimum Bending Radius” of a steel-tube-packaged sensor, often referred to as Fiber In Metal Tube (FIMT) or similar constructions, is a critical technical parameter primarily determined by several factors:

1. **Optical Fiber Characteristics:** The internal optical fiber itself has a bending tolerance. Exceeding this can lead to macro-bending loss, which attenuates the optical signal, or, in severe cases, cause the fiber to fracture.
2. **Metal Tube Characteristics:** The most significant limiting factor is the metallic packaging. The material, outer diameter, and wall thickness of the seamless steel tube dictate its flexibility. The tube must not undergo permanent deformation, such as kinking or flattening, as this would inevitably damage the optical fiber inside.
3. **Product Design:** The specific design of the packaged sensor, including how the fiber is integrated within the tube and any buffering layers, also plays a role in its overall bendability.

Therefore, the exact minimum bending radius is product-specific and should always be referenced in the technical datasheet of the particular OFSCN® product.

OFSCN offers several products utilizing metal tube packaging for enhanced durability and performance, such as the [OFSCN Alloy Tube Packaged Fiber Bragg Grating Strain Sensor](https://www.ofscn.net/fbg-products/strain-sensor.html), the [OFSCN® 300°C Fiber Bragg Grating Temperature Sensor](https://www.ofscn.net/fbg-products/temperature-sensor-300.html), and the [OFSCN® 500°C Fiber Bragg Grating Temperature Sensor](https://www.ofscn.net/fbg-products/temperature-sensor-350.html).

Here are some standard product images for these types of sensors:

 ![OFSCN Alloy Tube Packaged FBG Strain Sensor](https://forum.ofscn.net/uploads/default/original/1X/90c11b90deb49f0cd88a54ecac0d956bcddf353c.jpeg)  
 ![OFSCN Alloy Tube Packaged FBG Strain Sensor](https://forum.ofscn.net/uploads/default/original/1X/ae908bc1e181cfc4cdf263751c8670552a66522e.jpeg)  
 ![OFSCN Alloy Tube Packaged FBG Strain Sensor](https://forum.ofscn.net/uploads/default/original/1X/4a28a6be888c7e0965d6a522716233e8b6403b54.jpeg)  
 ![OFSCN 300°C FBG Temperature Sensor](https://forum.ofscn.net/uploads/default/original/1X/74932c0f3b71797adb12ca84a053059151051842.jpeg)  
 ![OFSCN 300°C FBG Temperature Sensor](https://forum.ofscn.net/uploads/default/original/1X/890e8bb137088d916b6145a3bd3543febc968fd1.jpeg)  
 ![OFSCN 500°C FBG Temperature Sensor](https://forum.ofscn.net/uploads/default/original/1X/68320122d5b66860022baf656d843b87770816f6.jpeg)

For further details, you can consult the relevant product pages on our website.