crystal fiberOne of the great advantages is the diversity of structures. It is precisely because of the different structure of crystal fibers that it is excellent in many aspects. Such as permanent single-mode transmission characteristics, tunable dispersion characteristics, high birefringence characteristics.

Here, I will introduce the advantages of crystal fibers in terms of dispersion.

There are two unavoidable factors in ordinary optical fiber, attenuation and dispersion. Dispersion refers to the pulse broadening caused by different refractive indices when light of different frequencies passes through an optical fiber. For digital systems, when an optical pulse is input, the output signal is a rectangular wave of a certain width. When light pulses are input continuously, the output rectangular light waves of a certain width will overlap. Therefore, the existence of chromatic dispersion causes an error in the communication system and limits the transmission rate of the optical pulse.

To solve a discrete problem, there are two kinds of solutions. One is to reduce the dispersion of the fiber, and the other is to use the dispersion compensation module.

In Scheme 1, ordinary optical fibers can be doped to reduce dispersion, but the dispersion of crystal fibers is related to its structure. Therefore, by adjusting the appropriate structure, a photonic crystal fiber with small dispersion can be obtained, and even a crystal fiber with zero dispersion can be obtained.

In Scheme 2, a module with negative dispersion is introduced behind a fiber with positive dispersion. The principle is as follows:

The dispersion compensation module is mainly usedcrystal fiber. Let L1 and L2 be the lengths of the ordinary optical fiber and the dispersion compensation optical fiber respectively, and D1 and D2 be the dispersion coefficients of the ordinary optical fiber and the dispersion compensation optical fiber respectively, which shall meet the following formula. While reducing the length of the compensating fiber L2, the absolute value of D2 should be increased as much as possible.

For ordinary dispersion compensation fiber, the dispersion is about -100 ~-200ps/(km.nm), while for dispersion compensation photonic crystal fiber, the dispersion can reach -2100ps/(km.nm).

In general, the dispersion range of the crystal fiber can be larger for ordinary optical fibers.

　　crystal fiberIt is of great significance to the research of materials. From the point of view of theoretical research, it is an important model for single-atom physicists to study the structural properties of materials, and the emergence of crystal fibers makes this model move from theory to reality, breaking the traditional theory, that is, crystal fibers cannot carry out many theoretical deductions at the same time. The fact, therefore, caused the rotation of physics. From an application point of view, this atomic-scale thickness and two-dimensional structure make it superior to the corresponding bulk material. In practical applications, since crystalline fibers are nanomaterials that cannot be distinguished by the naked eye, it is difficult to construct devices directly, and it is often necessary to assemble them into macroscopic materials.

Fiber is an excellent crystalline fiber-based macroscopic material. On the one hand, it has a larger surface area and smaller cross-sectional dimensions than other crystalline fiber-based macroscopic materials. It makes it easier for substances to enter the crystal fiber-based fiber and interact with the internal crystal fiber, which has a great influence on the application performance of catalysis, adsorption, electrode and other fields. On the other hand, crystalline fibers have flexibility and braidability. This is highly compatible with the important potential application areas of crystalline fibers in the development of electronic devices and smart wearable devices. Therefore, the preparation and application of crystalline fiber-based fibers has become an important direction in the development of crystalline fibers.