Across the sea of the world's "undersea optical fiber" ~ to the world the highest level a challenge of low-loss optical fiber ~
Create "optical communication era" the landmark of the fiber manufacturing process
By optical fiber communication -- a revolutionary idea was born in about 60 years ago.Then, in the '60 s, around the study of the fiber to promote real, after entering the 70 s, the pace of the optical fiber practical speed increasingly.In this context, including the NTT (at that time the Japanese telecommunications telephone commune) and sumitomo electric three cable manufacturers, set up the system of optical fiber joint research.In this process, we developed the known as "VAD method" has the excellent production of optical fiber manufacturing methods.After entering the 80 s, we through the improvement of VAD method, realizes the higher quality and lower loss of fiber production, entered into a formal commercial stage.
Production of optical fiber, the first to the glass, as the main body of the preform in the heating at the same time, to form a filament, was made from the fiber.The point is that the same axial, in continuous lift, at the same time, through the accumulation of porous glass, make a large optical fiber preform, so as to increase production.In addition, because produce fewer impurities of optical fiber preform, therefore also implements the low loss this top quality.The establishment of the "VAD method" and evolution, become a big step towards "optical communication era".
In order to reduce transmission loss as the goal
Let the world wonder low-loss optical fiber "Z - fiber" was born
"VAD method" is established in the process of subject, is the "low loss", namely reduce the transmission loss.Then the transmission loss what is?When the light in the fiber optic transmission, after a certain distance, part will be fiber to the external light scattering, or due to the impurities inside the glass, part of the light is absorbed and attenuation, this process is the transmission loss.When the transmission loss increases, the optical signal will be difficult to reach, and then to communications limited amount of data and communication speed fall damage such as communication quality and reliability of the situation (restore the degradation of the optical signal, you need to use the optical amplifier).Therefore, for sumitomo electric group of optical fiber technology team, realize the low-loss optical fiber, is the pursuit to the biggest subject.Now as optical communication business enterprise to draw minister is onishi tzu is also one of the staff dedicated to the development of low loss optical fiber technology.
"To achieve low loss, just need to improve the transparency of glass.Although "VAD method" to try to eliminate impurities, but as the additive of germanium is a must.Although fiber is made up of fiber core and cladding, but will seal in internal and transmission of light, you will need to refractive index difference between fiber core and cladding.To increase the refractive index of fiber core, it is necessary to add germanium.However, the company pursue is the ultimate low loss.Therefore, predecessors and focus on development of germanium fiber core optical fiber.In order to ensure that the refractive index difference, we added in the cladding the fluorine, to decrease the refractive index of the maintain transparency (low loss) of the new optical fiber was named "Z - fiber", and to be able to come out ".
That was in 1986.To show the value to, in the past of optical fiber transmission loss of 0.20 dB/km, and the new product is achieved 0.154 dB/km (research/product level of 0.17 dB/km) * a surprisingly low loss value, has caught the world by surprise.
Before long, sumitomo electric group of optical fiber technology team will they judge the necessary and the most suitable areas - low loss optical fiber, as its goal market.Low loss this advantage most effectively play areas, is a long distance communication, its most large-scale projects for crossing the sea "undersea optical fiber.Worldwide, 1988, no. 8 "TAT - 8" transatlantic cable has introduced the optical fiber, then in 1989, no. 3 "TPC - 3" across the Pacific Ocean cables also completed the packtized.As a result, the international long distance call to become accustomed to, then in order to further expand the transmission capacity, people are constantly advancing.In 1992, adopted the "Z - fiber" of 4, cable "TPC - 4" across the Pacific to construction, realizes the TPC - 2 times the transmission capacity of 3."Z - fiber" is greatly enhanced by low loss of high capacity.The need to pay attention to is that although the high-performance optical transceiver also played a huge role, but the importance of low loss undersea optical fiber has been widely cognitive at this stage.
* dB (dB) is the unit of transmission loss.0.17 dB/km per 1 km said there will be a loss of 0.17 dB, with this value multiplied by the length of the transmission path, can estimate the loss of transmission path integral.
Across the Pacific Ocean is committed to solve the problem of "dispersion"
In this way, low loss optical fiber has been applied to submarine cable, but on the other hand, new task and highlight.That is "dispersion" problem.The evolution of the optical wavelength associated with the use of semiconductor laser, the wavelength extending to 0.8 ㎛ ㎛ ㎛, 1.3 and 1.55, but bring the huge impact, is 1.55 ㎛.1.55 ㎛ band is considered to be one of the optical fiber transmission loss minimum band, suitable for long distance transport.But sumitomo electric group "Z - fiber" in 1.55 although ㎛ band is the world's lowest loss, but because of "dispersion" this feature is not zero, transmission capacity is limited.Dispersion refers to, because the wavelength is different, lead to the light transmission rate of different phenomenon.Due to have a small number of wavelengths diffusion, dispersion, pulse will spread in the time domain wave form, and unable to realize high speed transmission.Sumitomo electric的研究团队在维持低损耗的前提下，开始致力于在1.55㎛波段下实现零“色散”的研究。
"How to suppress the dispersion, which is close to zero?To do this, you need by additives, change the shape of the distribution of fiber core and cladding, and then change the wavelength dispersion characteristics.Although we tried a variety of methods, but no matter how to try, the value of transmission loss is still high.In the end, everyone with unwilling, had to give up the relevant development ".
Then undersea optical fiber using is still growing, but these optical fiber and fiber "Z -" implemented by low loss optical fiber is different, use of the past will be 1.55 ㎛ band dispersion control use of germanium optical fiber for close to zero.
Firm faith of the world's highest level very low loss optical fiber
Since 2002 about 10 years, because of the IT industry economic environment confusion, sumitomo electric group of submarine optical fiber business have also stalled.Even under such a background, based on "low transmission loss optical fiber will be a great help to the society" this generation inheritance of faith, constantly promoting aiming at extremely low loss optical fiber development.Around 2010, with the appearance of digital coherent reception technology, dramatic changes have taken place.This technique can receive signals distortion due to the dispersion directly, through the signal processing circuit of the calculus, against distortion correction processing.With the utility of this technology into an opportunity, a sharp slowdown in to the requirement of the solving of dispersion characteristics of optical fiber, and sudden rise to the requirement of low loss.Take advantage of this opportunity, we enhance development resources to research and development and the achievements in 2013.Development of one of the core members, is now hirano was shaking of the overseas division of optical communication division.
"In order to realize the transmission loss minimization, will have not reached the height of the glass transparency to ever became our main task.Generally think that the refractive index of fiber glass is equal, but in fact it is "volatile".That is to say, it is not homogeneous.We through the way of nanoscale promote the minimization of its volatility.That is to say, we firmly believe that reduce the volatility of the glass, increase its transparency, can achieve very low loss optical fiber ".
In 2013, after Mr. Hirano people such as research and development, product level is 0.154 dB/km optical fiber was born, sumitomo electric optical fiber once again attracted the attention all over the world.This is the beginning of coming back to life.After further accelerate development, in 2017, the research level achieves the transmission loss of 0.142 dB/km (product level, 0.150 dB/km), refresh the world record for the optical fiber transmission loss.With the development of parallel hirano, were is the sharp increase in submarine cable fiber application, eventually won the world's leading market share position.
Through innovative technology and dedication to create unprecedented products
The initiatives of the development of a new generation of optical fiber has been accelerated.Responsible for the work of one of them, is the optical communication of optical transmission media research institute of hasegawa bodybuilding.
"This research institute, extremely low loss the theme of the development of optical fiber is our forever pursuit.We also need to set a new world record.I hope that in certain cost and productivity, accurately grasp the needs of customers at the same time, promote the related research and development.On the other hand, each one optical fiber transmission capacity is close to the limit.In response to this, I hope to increase more fine some core optical fiber and other new development can also challenge ".
Certain research present situation and the market, for the promotion of sumitomo electric group fiber enterprise prestige in the world market of this responsibility, is belonging to optical communication division and optical communications research institute work history of dell wild margin.
"Continue to visit customers and listen to their needs, it is very important.Although it is true that the low loss fiber products of the company's core technology, but the customer is not only the pursuit of quality, also need to cut costs.I hope that in the pursuit of cutting-edge technology, can provide the most suitable optical fiber.Also want to actively develop into new markets worldwide.
Sumitomo electric group of fiber products has about 40 years of history."Many elder people don't give up, with all its strength" (onishi) got real thoughts and beliefs.Obsessed with unique technology, "to create an unprecedented products", unremitting efforts will carve out a new era.
