roccoschili Page 397
Page 397
In the office, I found a telegram from Changchun, reporting a piece of extraordinary information.
"The first furnace of ultra-high-purity quartz glass was smelted next door!"
The telegram was sent by Wang Dayan of the Changchun Institute of Optoelectronics.
The next door he was talking about was the Changchun Optical Instrument Factory next to the Changchun Institute of Optoelectronics.
Wait a minute, Changguang reported once a few months ago that they made Suba—from Suliu to Suba, which is still military binoculars.There are two major difficulties in attacking the artillery scope and the sniper rifle scope.
This is the progress of lens research and development.Optical glass... It seems that Changguang is indeed repeatedly testing various optical glass formulas.So they tinkered with ultra-high-purity quartz glass?
Tang Hua immediately called the Physics Department of Tsinghua University.
Which group is the laser communication group led by Mr. Zhao Zhongyao?It seems to be the second group.
In December 1951, the second group Zhou Guangzhao completed the laser communication between two computers with laser in the laboratory.This is a beam of laser beams that communicate directly in the air at a distance of 12 meters, which is the most basic principle model.
Because the optical fiber can't be produced yet, it has been stuck at this step for more than a year, which makes Mr. Zhao feel embarrassed.
Now ultra-high purity quartz glass is out, so?
……
The Tsinghua Department of Physics waited for a long time before someone answered the phone.It was neither Zhao Zhongyao nor Zhou Guangzhao who spoke.
"Hello Minister Tang, Mr. Zhao received a telegram about a few days ago. After reading it, he jumped up and packed his luggage immediately. The next day, he went to Changchun with Zhou Guangzhao and a few graduate students."
hiss……
It seems that Wang Dayan sent telegrams to Tang Hua and Zhao Zhongyao at the same time.
Teacher Zhao seemed to have waited too long and was impatient.
Tang Hua wondered if he should also go there, but it seemed that he only contributed one paper, and the rest of the experiments and calculations were done by the second laser group, so he didn't want to steal their limelight.
……
Changchun.
Zhao Zhongyao and Zhou Guangzhao got off the car in Changchun and lived in Changguang. After putting down their luggage, they went to the optical glass production workshop.
"Trouble to remelt, if possible, do another job to remove impurities." Zhao Zhongyao said.
"Just follow Professor Zhao's instructions."
Wang Dayan and Zhao Zhongyao arrived at the scene together.Now Changchun Optoelectronics Institute and Changguang have been brought together as one, with Wang Dayan as the director, and also Changguang's deputy factory director and technical expert.
"In addition, the optical glass workshop transferred two to three technicians with the best skills. After the political review, they merged with Professor Zhao's team to form a technical research team."
"Da Yan, thank you for supporting our work."
"In Tsinghua University, we have cooperated for such a long time, so there is no need to say polite words," Wang Dayan said, "This is in Changchun. Of course, Changchun is my decision."
It has been two years since Wang Dayan came to Changchun Institute of Optoelectronics, and the tone of his speech seems to admit that he is from the Northeast.
"Da Yan, I heard that you have been working on a key project for a long time?"
Wang Dayan: "Yes, yes....Hey, this project is too high-level, I'm sorry. I don't know if I can make an application report. After you finish this project, you can also help us in Changchun."
……
In 1880, Alexander Bell invented the "optical talking machine".He concentrated the sunlight into a very narrow beam and irradiated it on a very thin mirror. When the human voice made the thin mirror vibrate, the change in the reflected light caused the sensing detector to change and change the resistance value.The receiving end uses the changing resistance value to generate current to restore the original sound.
After Bell's experiment was successful, he wrote a sentence in the experiment log: "I heard the laughter and singing of the light."
Then... This technology has not moved for decades. It was not until December 1951 that Zhou Guangzhao began to use light to transmit binary numbers, which was considered a step forward.
Before the invention of optical fibers, the principle of total internal reflection of glass was also used to transmit light. For example, dentists used curved glass rods to guide light into the patient's mouth for surgical lighting, which was later developed into gastroscopy.
Even in 1951, photophysicist O'Brien proposed the concept of cladding.
In 1960, when the laser was invented, someone immediately used glass fiber to transmit the laser around the bend.
But in ordinary glass, half of the energy is lost when light travels 3 meters.It can be used for human internal organs inspection, but it is impossible to use it for long-distance optical communication.
Then in 1966, Kao published "Optical Frequency Dielectric Fiber Surface Waveguide", and came to an epoch-making breakthrough conclusion in the history of optical fiber communication: when light is transmitted in glass, the loss is mainly caused by the impurities contained in the material, not the glass itself.
Gao Kun predicted that if ultra-high-purity quartz glass is manufactured, when the light beam propagates at least 500 meters in the optical fiber, there will still be 10% energy remaining.That is, it is possible to reduce the loss to 20dB/km.
Corning Corporation of the United States saw that it would not be too difficult to smelt a furnace of ultra-high-purity quartz glass without adding anything, so they tried it, and the result was that 20dB/km optical fiber was really pulled out.Since then, optical fiber communication has officially begun to kick off.
……
As for now...
Teacher Zhao and Zhou Guangzhao certainly figured out that the transmission loss of glass fiber is caused by impurities.
The technical reserve of the laser is also enough.
Zhou Guangzhao's laser (through the air) computer communication equipment has also got the third edition.
"According to Mr. Tang's estimate, the optical fiber should have a double structure. The core part is made of high-refractive-index glass, and the surface part is made of low-refractive-index glass or plastic. Light is transmitted in the fiber core and continuously undergoes total reflection at the junction of the surface layers. , forward transmission along the zigzag shape." Zhao Zhongyao said, "Changguang can't do plastic cladding now, so let's try low-refractive index glass cladding."
Zhou Guangzhao: "Mr. Zhao, what about the thick fiber core we pull?"
"Minister Tang said that the hair can be as thin as it is. If you want to be more conservative, you can pull 0.1mm, 0.2mm or 0.3mm when you conduct the first principle experiment. As for now," Zhao Zhongyao looked at the long light placed around equipment, covered his face and said, "Pull the 0.5mm one."
Chapter 21, save a small blast furnace
In January 1951, Tang Hua decided that the second group of lasers was the communication group, with Mr. Zhao as the team leader. He also stated that the postgraduates participating in the second group would be master-doctoral students.
This means that the field of laser communication may not be able to break through in three years, so prepare for research for six years or even longer.
The subsequent development seems to prove that it is really not easy to develop wire laser transmission communication technology. In December 1951, Zhou Guangzhao used laser light transmitted in the atmosphere to carry out the first binary data communication between computers, and then got stuck at this step.
In the blink of an eye, it was October 1953, two years and 10 months had passed.
Three years of master's degree.More than three years... It seems that I really want to study for a doctorate?
Now the theoretical research of the second group of lasers is complete, and the principle verification (using the method of atmospheric transmission) has also been done.Special lasers, modulation and demodulation systems, and computer data access devices have all been made or have spectrum.Only the optical fiber is not easy to do.
Tang Hua's paper pointed out that ultra-high-purity glass should have an extremely low loss rate, but when this paper was published, China could not even manufacture binoculars-the Changchun Optical Instrument Factory was still a construction site.
In the plan for Changchun Optical Instrument Factory, the ultra-high-purity quartz glass should have been smelted for the first time in mid-1954, and now it has been advanced by more than half a year.
Therefore, Zhao Zhongyao and Zhou Guangzhao's surprise should be attributed to the cadres and workers of Changchun Optical Instrument Factory. They lived up to expectations and completed the factory infrastructure on time. After the factory started operating, they were divided into two groups. One group made optical lenses and telescopes, and constantly honed the processing technology; Another passer-by pondered various formulations of glass, including smelting ultra-high-purity quartz glass.
"The three pieces of glass all come out of this furnace," Zhao Zhongyao held the measuring instrument, "the measured loss rate of the first piece is 21.10dB per kilometer, the second piece is 21.13dB per kilometer, and the third piece is 21.09dB per kilometer. It is [-]dB per kilometer. It is already very close to Minister Tang’s prediction.”