Two 、what are the outstanding advantages of optical fiber transmission
Strong anti-interference ability
Because the basic component of optical fiber is quartz, it only transmits light, does not conduct electricity, and is not affected by electromagnetic fields. The optical signal transmitted in it is not affected by electromagnetic fields. Therefore, optical fiber transmission has strong resistance to electromagnetic interference and industrial interference. Because of this, the signal transmitted in the optical fiber is not easy to be eavesdropped, so it is conducive to confidentiality.

high fidelity
Because optical fiber transmission generally does not require repeater amplification, no new nonlinear distortion will be introduced due to amplification. As long as the linearity of the laser is good, television signals can be transmitted with high fidelity. The actual test shows that the three-beat ratio C/CTB of the carrier combination of a good AM fiber system is above 70dB, and the intermodulation index cM is also above 60dB, which is much higher than the nonlinear distortion index of the general cable trunk system.

Reliable performance
We know that the reliability of a system is related to the number of devices that make up the system. The more devices there are, the greater the chance of failure. Because the fiber optic system contains a small number of devices (does not require dozens of amplifiers like the cable system), the reliability is naturally high. In addition, the service life of the fiber optic equipment is very long, and the trouble-free working time is 500,000 to 750,000 hours. Among them, the laser in the optical transmitter has the shortest lifespan, and the minimum lifespan is also more than 100,000 hours. Therefore, the working performance of a well-designed, correctly installed and debugged optical fiber system is very reliable.

Costs keep falling
Someone proposed a new Moore's Law, also known as the Optical Law. The law states that the bandwidth of optical fiber transmission information doubles every 6 months, while the price decreases by 1 times. The development of optical communication technology has laid a very good foundation for the development of Internet broadband technology. This clears the last obstacle for large-scale cable television systems to adopt optical fiber transmission. Due to the abundant sources of materials (quartz) for making optical fibers, with the advancement of technology, the cost will be further reduced; while the copper raw materials required for cables are limited, the price will be higher and higher. Obviously, optical fiber transmission will occupy an absolute advantage in the future and become the most important transmission method for establishing the cable television network in the whole province and even the whole country.