The core working principle of fiber optic adjustable attenuator is to change the propagation state of optical signals in a controllable manner, so that some optical energy is absorbed, reflected or scattered, thereby accurately adjusting the attenuation of optical power without changing the polarization state and wavelength characteristics of the optical signal.
- Attenuation chip: By mechanically moving the neutral density filter, the insertion depth or area of the filter on the optical path is changed, and the filter absorbs light energy proportionally to achieve attenuation adjustment.
- Fiber bending type: By utilizing the radiation loss characteristics during fiber bending, the bending radius of the fiber is controlled by a mechanical device. The greater the degree of bending, the more optical signal leakage and attenuation will occur.
- Micro displacement reflection type: By fine-tuning the position of the reflector or prism, the reflection path of the optical signal is changed, so that some light cannot be coupled back to the output fiber, achieving controllable attenuation.
- Liquid crystal: Utilizing the electro-optic effect of liquid crystal materials, the arrangement of liquid crystal molecules is changed by applying different voltages, thereby adjusting their ability to absorb or modulate light, and achieving attenuation control of electrical signals.
- MEMS technology formula: Based on microelectromechanical systems, the micro mirror is driven by electrostatic or electromagnetic forces to deflect, change the direction of light propagation, adjust the optical power coupled to the output fiber, with fast response speed and high adjustment accuracy.
- Magneto optical/electro-optic modulation: By utilizing the magneto optical effect or electro-optic effect, the optical properties of materials (such as refractive index) are changed, resulting in controllable loss of optical signals during transmission and achieving attenuation adjustment.
All types follow the core logic of "controllable loss": the optical signal of the input fiber is collimated and interacts with the attenuation element, causing some optical energy to be lost, while the remaining optical signal is focused and coupled to the output fiber. By adjusting the state of the attenuation element (such as position and characteristics), the loss ratio can be precisely controlled, achieving continuous or stepwise adjustment between 0 and the maximum attenuation value, while maintaining the basic transmission characteristics of the optical signal stable throughout the entire process.