To answer this question, we must first find out what is an optical cable and what is the signal transmitted by the optical cable, and then we can understand how tens of thousands of signals exist in a thin optical cable at the same time
Have you ever seen a cable? The rope is twisted into many strands. The physical composition of optical cable can be compared with that of cable. Optical cable is also a kind of "cable", but its "thin rope" is optical fiber, optical fiber is the main body of optical cable, and there is a protective layer outside to protect it. Of course, the function of optical cable is not used to pull or pull like cable, but to transmit signals. So, what is the signal transmitted by optical cable? As the name suggests, optical cable transmits optical signal, and optical fiber is the medium of optical signal transmission.
The reason why the thin optical cable can transmit tens of thousands of optical signals at the same time is only because of the support of optical signal multiplexing technology. Optical signal multiplexing technology is a technology that enables the optical signals generated by multiple light sources to be transmitted in the same optical fiber. Because light is also an electromagnetic wave, each light wave can be modulated (modulation wavelength and frequency), and then coupled to an optical fiber for transmission through an optical recombiner. You may ask, how can we distinguish when the optical signals are mixed together? Don't worry, with the previous modulation and recombination, each signal has its own characteristics for identification. They have their own frequency or wavelength. When the optical signal reaches the receiving end, the decoupler will separate the different signals, so that multiple signals can be transmitted in one optical fiber.
An optical cable contains many optical fibers. There are many light waves on each optical fiber, and tens of thousands of signals are transmitted smoothly in the same optical cable.