How many "colors" can a fiber transmit?

International Zone (English) OFSCN Knowledge Base (Public)
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Can dozens of different wavelengths travel through a single fiber simultaneously?Will they “collide” with each other?

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Yes, a single optical fiber can simultaneously transmit dozens or even hundreds of different wavelengths (colors) without them “colliding” with each other. This is a fundamental principle used in both optical communications and optical fiber sensing.

1. Why don’t they collide?

In physics, this is known as the Principle of Superposition. Light waves of different frequencies (wavelengths) do not interact with each other in a linear medium like silica glass. They occupy the same physical space within the fiber core but remain independent in the frequency domain.

In the industry, this technology is called Wavelength Division Multiplexing (WDM).

2. Application in FBG Sensing

At OFSCN (Beijing Dacheng Yongsheng Technology Co., Ltd.), we utilize this property to perform Quasi-Distributed Sensing. By writing multiple Fiber Bragg Gratings (FBGs) with different center wavelengths onto a single fiber, we can measure temperature or strain at many different points simultaneously.

  • Multiplexing Capacity: On a single fiber string, we typically place anywhere from a few to dozens of FBG sensors.
  • The Constraint: The limit is not “collision,” but rather the available bandwidth of the light source (interrogator). For example, if your interrogator operates from 1525nm to 1565nm (C-band), and each sensor requires a 2nm “buffer” to account for its wavelength shift under heat or pressure, you could theoretically fit 20 sensors on one fiber.

3. DCYS (OFSCN®) Related Products

We specialize in high-temperature and high-strength FBG sensors that leverage this multi-point transmission capability.

Relevant Products:

By using different wavelengths, these sensors can be “daisy-chained” along a single cable, significantly reducing the complexity of wiring in large-scale engineering projects.

If you have questions about the specific wavelength spacing required for a project, feel free to ask.