Today's fiber optic patch cord markets are very complex. The price of a conventional 1 meter SC single core patch cord ranges from $ 0.3 to more than $ 2. What are the reasons for such a big price difference of fiber optic patch cords? Below are the various factors which influence the price of fiber optic patch cords.
1. Different Quality of Raw Materials
Fiber optic patch cord is composed of optical cable in the middle and connectors at both ends. The optical cable is made up of four parts from the inside to the outside: fiber, inner sheath, aramid yarn and outer sheath.
(1) Optical Fiber
Optical fiber is the core raw material in fiber optic cables. Formal manufacturers generally use grade A fiber cores. Low-cost and inferior cables are often made from grade C or D fiber cores. Sometimes there are cases where OM3-300 fiber is used to pretend to be OM4 fiber. Small factories lack the necessary test equipment for judgment on the quality of optical fiber. Because such optical fibers cannot be identified by the naked eye, problems often encountered during construction are that excessive loss leads to short transmission distance and uneven core diameter leads to the difficulty to butt with pigtails or large loss after butting.
(2) Aramid Yarn
Aramid is a new type of high-tech synthetic fiber with super high strength, high-temperature resistance and acid & alkali resistance. Its strength is 5-6 times that of steel wire, and it does not melt or be decomposed at a temperature of 560 degrees. Aramid also has good insulation and anti-aging properties. The invention of aramid is considered to be a very important historical process in the material industry. The main material of current bulletproof vests and military helmets is generally aramid. The purpose of using aramid in indoor fiber optic cables is to protect tight buffer fiber from mechanical tension.
Aramid yarn is roughly divided into Kevlar, imported aramid yarn, domestic aramid yarn and polyester yarn according to the difference of its material. Kevlar is the patented trade name of para-aramid developed by DuPont in the United States, and its price is high. In addition to DuPont, the major foreign aramid yarn manufacturers include Teijin in Japan and Kolon in South Korea. Their prices are lower than DuPont's. As the performance of aramid yarn made in China tends to stabilize, the price is relatively low. Chinese aramid yarn manufacturers mainly include Yantai Tayho, Suzhou Zhaoda, Sinopec Yizheng and Bluestar Chengrand.
Aramid yarn is one of the main cost components of indoor fiber optic cables. Due to the high cost of aramid yarn, inferior indoor cables may be made from fewer strands of aramid yarn or from polyester yarn which is similar in appearance to aramid yarn instead to save costs. The price of polyester yarn is less than one-tenth of that of imported aramid yarn. But polyester yarn can hardly bear any tension so that the optical fiber is easily broken or damaged when laying. Moreover, polyester yarn is not resistant to high temperature and not flame retardant. Based on these characteristics, the way to distinguish aramid yarn and polyester yarn is very simple -- just burn it with fire. The following are burning test videos of aramid yarn and polyester yarn.
Aramid Yarn Burning Test
Polyester Yarn Burning Test
The outer sheath materials of indoor fiber optic cables are mainly polyvinyl chloride (PVC), flame-retardant PVC, low smoke zero halogen (LSZH) or flame-retardant LSZH. LSZH cable jacket is composed of thermoplastic or thermoset compounds that emit limited smoke and no halogen when exposed to high sources of heat. The price of LSZH is higher than that of PVC. The price of flame-retardant sheath is different according to the flame-retardant grade.
The high quality outer sheath should be easy to be peeled off and its appearance should be smooth, bright and elastic. Inferior cable jacket has poor surface roughness, what’s more, it is easy to stick with tight buffer fiber and aramid yarn.
Ferrule is the core component which affects the performance of fiber optic connector. The quality of ferrule directly affects the precise center connection of the two optical fibers. Ferrule is made of ceramic, metal or plastic. Ceramic ferrule is widely used. There are two situations where the quality of connectors is not good due to the ceramic ferrule.
① Using ferrules with a concentricity of 1.5 um instead of 1.0 um for production. Rotating connector to adjust the position of cores during the test in order to make loss value appear to enter qualified range.
② Using recycled ferrules. Since second-hand ferrules have already undergone a grinding process when they are first made into connectors, the exposed length of the ferrules may be too short which will cause large access loss when they are used again.
2. Different Technical Standards
(1) Fiber End Face
As shown in the figure below, the fiber end face is divided into three areas ABC. There must be no spots, scratches or other defects in the fiber core area A and the fiber cladding area B on the high-quality end face. Otherwise, they will cause obstacles to optical signal transmission and affect the values of insertion loss and return loss.
(2) Insertion Loss & Return Loss
The optical performance of fiber optic connectors is mainly measured by two basic parameters, insertion loss and return loss. Insertion Loss (IL) refers to the optical power loss caused by the connection. It describes the optical loss between two fixed points in the fiber, usually generated by the horizontal deviation between two fibers, the vertical gap between two connectors or end face quality. The unit is expressed in decibels (dB). And the value of IL is generally required to be less than or equal to 0.3dB.
Return Loss (RL) refers to the parameter of signal reflection performance which describes the power loss of optical signal return or reflection. The unit is also expressed in decibels (dB). The typical RL value of a general APC connector is about 60dB, and for a UPC connector, it is about 50dB.
During the IL and RL test of Sun Telecom's fiber optic connector, each end is continuously measured 3 times. Each measurement value meets the following requirements, and the insertion loss change is less than 0.2dB. The average value of 3 times will be recorded if it is necessary to record the actual value.
||SM (Wavelength: 1310/1550nm)
||MM (Wavelength: 850/1300nm)
(3) Plug Stability
According to the IEC 61753-1 standard, the plugging durability of fiber optic connectors should be greater than or equal to 500 times, and the change in insertion loss should be less than or equal to 0.2dB. The attenuation of inferior connectors will increase after repeated plugging and unplugging many times. Therefore, plugging durability is usually considered to be one of the most important indicators reflecting the stability of fiber optic connectors.
3. Different Strengths of Manufacturers
The production steps of fiber optic patch cords can be divided into three parts: an assembly of cables and connectors, end face polishing, inspection and testing. The production of high-quality fiber optic patch cords has high requirements for many aspects. There are many factors that affect the quality and price of patch cords, such as the efficiency of production scale, the automation of the production equipment, the completeness and accuracy of test instruments, the proficiency of operators, the quality control ability and the lean production site management ability, etc.
All in all, when choosing a fiber optic patch cord supplier, you should consider the cost performance and the supplier's product quality, technical strength and service quality, not just the cheapest price. As a professional fiber optic solutions provider, Sun Telecom not only provides cost-effective fiber optic patch cords, but also offers turnkey solutions for helping build an integrated or sectional patch cord production line based on more than 30 years of experience.