Majid Wali
An optical fiber, is a flexible, transparent fiber made by drawing glass (silica) or plastic to a diameter slightly thicker than that of a human hair. Optical fibers are used most often as a means to transmit light between the two ends of the fiber and find wide usage in fiber-optic communications, where they permit transmission over longer distances and at higher bandwidths (data transfer rates) than electrical cables. Fibers are used instead of metal wires because signals travel along them with less loss.Specially designed fibers are also used for a variety of other applications, some of them being fiber optic sensors and fiber lasers.
The field of applied science and engineering concerned with the design and application of optical fibers is known as fiber optics. The term was coined by Indian-American physicist Narinder Singh Kapany. Optical fibers typically include a core surrounded by a transparent cladding material with a lower index of refraction. Light is kept in the core by the phenomenon of total internal reflection which causes the fiber to act as a waveguide. Fibers that support many propagation paths or transverse modes are called multi-mode fibers, while those that support a single mode are called single-mode fibers (SMF).
Multi-mode fibers generally have a wider core diameter and are used for short-distance communication links and for applications where high power must be transmitted. Single-mode fibers are used for most communication links longer than 1,050 meters (3,440 ft). Being able to join optical fibers with low loss is important in fiber optic communication.This is more complex than joining electrical wire or cable and involves careful cleaving of the fibers, precise alignment of the fiber cores, and the coupling of these aligned cores. For applications that demand a permanent connection a fusion splice is common. In this technique, an electric arc is used to melt the ends of the fibers together. Another common technique is a mechanical splice, where the ends of the fibers are held in contact by mechanical force. Temporary or semi-permanent connections are made by means of specialized optical fiber connectors. Optical fiber is used as a medium for telecommunication and computer networking because it is flexible and can be bundled as cables. It is especially advantageous for long-distance communications, because infrared light propagates through the fiber with much lower attenuation compared to electricity in electrical cables.
This allows long distances to be spanned with few repeaters. Types of optical fibers include Multi mode fiber, Single mode fiber and Special purpose fiber. Glass optical fibers are almost always made from silica, but some other materials, such as fluorozirconate, fluoroaluminate, and chalcogenide glasses as well as crystalline materials like sapphire, are used for longer-wavelength infrared or other specialized applications. The Pakistan-China Fiber Optic Project is an 820 kilometer long optical fiber cable laid down between the Khunjerab Pass on the China-Pakistan border and the city of Rawalpindi. It has been constructed as part of the China–Pakistan Economic Corridor at an estimated cost of $44 million. Groundbreaking on the project took place on May 19, 2016, in the city of Gilgit. The line was first envisaged in 2009, with Pakistan and China signing an agreement in 2013 to implement the project.However the project was not implemented until being included as part of the China Pakistan Economic Corridor. Placement of the line will take an estimated 2 years, and will bring 3G and 4G connectivity to the Gilgit-Baltistan region. The line will connect the Transit Europe-Asia Terrestrial Cable Network with that of Pakistan, which currently transmits its telecom and internet traffic through four undersea fiber optic cables, with another three undersea fiber optic cables under construction. 466.54 kilometers of the route will be located in Gilgit-Baltistan, while 287.66 kilometers will be laid in Khyber Pakhtunkhwa province, 47.56 kilometers will be in Punjab province, and 18.2 kilometers in Islamabad Capital Territory. which will be extended to Gwadar. The project is financed by the Exim Bank of China at a concessionary interest rate of 2%, versus the 1.6% typical of other CPEC infrastructure projects.
The project has been completed and inaugurated in July 2018. Delegation of leading Chinese enterprise SUNWALK group led by CEO SUNWALK Pakistan Mr.Tony Lan called on Federal Minister for IT and Telecommunication Syed Amin Ul Haque. SUNWALK group is working extensively in the area of Fiberization in China and other countries and now keenly focusing on Pakistan market. Mr. Lan briefed the Federal Minister for IT about investment plans of SUNWALK group for deploying nationwide Optical fiber network and help in enabling the broadband growth in Pakistan. Mr. Lan mentioned that their group is ready to invest around 2 Billion USD over the next 8-10 years. Federal Minister for IT Syed Amin Ul Haque expressed his thanks and appreciation to SUNWALK group for showing their interest in Pakistan’s market and assured the fullest support to the group in their initiatives. He said that Fiber network is essential for the 4G\5G growth and Digitalization in Pakistan. SunWalk group initiatives will contribute more in cementing PAK-CHINA ties.