单模与多模光纤电缆

光纤电缆基于这样的想法，即光可以通过全内反射限制在弯曲的玻璃棒内。如今，光纤用于将电话、电视和计算机信号从一个地方传送到另一个地方。

光纤由被包层包围的纤芯组成，其中纤芯是密度较大的介质，而包层是相对稀有的介质。根据光的传播方式，有两种光缆：

1. 单模光纤电缆：
   SMF（单模光纤）是一种光缆，设计用于仅传输单模光，即横模。这些用于信号的长距离传输。
2. 多模光纤电缆：
   多模光纤电缆是一种通过其直径较大的芯传输数据的光纤电缆，使平均单模收发器能够通过多模光传播。然而，由于模态色散，这限制了可能的传输链路的最大长度。因此，这些光纤用于信号的短距离传输。

Single-Mode Optical Fiber Cable	Multi-Mode Optical Fiber Cable
Designed to carry only a single mode of light – transverse mode.	Designed to carry multiple modes of light at once.
Used for long-distance transmission of signals.	Used for comparatively shorter distance transmission of signals.
Narrower modal dispersion is present.	A large range of modal dispersion is possible.
They have a smaller core of about 9 micrometers (µm) in diameter.	The core diameter is 50 µm or above.
Practically there is no or less degradation of signals.	There is much more degradation of signals.
Handling or manufacturing them is quite difficult as coupling light becomes difficult with distance.	Easier to manufacture and handle.
Not only the cable cost but on average, single-mode transceivers are costing 1.5 to 4 or 5 times the cost of the multimode transceivers depending on the data rate.	Multi-mode optical fiber cables for usage in short distances are more cost-effective compared to single-mode fibers.
Single-mode fibers can be classified as the OS1 and OS2 types having applications at wavelengths 1310nm and 1550nm respectively.	OM1, OM2, OM3, OM4, and OM5 fiber types are the most common forms of multimode fiber.
Single-mode fiber can carry signals at a much greater speed.	Signal speed is relatively slower in multimode fiber cables.
A laser, or laser diode, is used in single-mode bandwidth devices to create light that is injected into the cable.	A light source for multimode devices is generally an LED or a laser.
Single-mode fibers have higher bandwidth compared to multimode fibers as much as 100,000 GHz.	Multimode fibers have lower bandwidth to offer.