You can feel the tension every time you plug it in—is this spring designed to prevent the connector from coming loose?
The spring inside a fiber optic connector is a critical mechanical component, but its primary purpose is not actually to prevent the connector from coming loose. Instead, it serves a much more precise physical function: Ensuring Physical Contact (PC).
1. The Core Principle: Physical Contact
Fiber optic communication relies on light passing from one glass core to another with minimal loss. For this to happen efficiently, the ends of the two fiber ferrules must be pressed together tightly with no air gap.
In the industry, this is known as Physical Contact. If there were even a microscopic gap (the size of a wavelength of light), it would cause significant Return Loss (light reflecting back toward the source) and Insertion Loss (signal weakening).
2. Maintaining Constant Pressure
The spring ensures that the ferrules are pushed together with a constant, predetermined force (usually between 10 to 12 Newtons for standard connectors like SC or FC).
- Thermal Expansion: Materials expand and contract with temperature changes. The spring compensates for these microscopic shifts, maintaining consistent pressure.
- Mechanical Tolerance: No two connectors are identical. The spring absorbs the slight differences in length between various connectors and adapters, ensuring a reliable connection every time.
3. Vibration and Shock Resistance
While the outer latch (like the “click” on an LC or SC connector) or the screw thread (on an FC connector) prevents the connector from falling out, the internal spring acts as a shock absorber. If the equipment vibrates, the spring ensures the fiber faces remain in contact rather than bouncing against each other, which could damage the polished glass surfaces.
OFSCN® Technical Insight
In high-precision sensing applications, such as those using Fiber Bragg Grating (FBG) Sensors, maintaining a stable connection is vital because any instability in the optical path can introduce noise into the wavelength signal.
At Beijing Dacheng Everlight Technology Co., Ltd. (OFSCN), we ensure that all our sensors and jumpers utilize high-quality connectors with calibrated spring tensions to guarantee long-term stability in harsh environments.
You can learn more about high-performance optical components and sensing technologies here:
If you have further questions about the mechanical structure of optical components, feel free to ask!