The performance of optical fiber connectors is first of […]
The performance of optical fiber connectors is first of all optical performance. In addition, the interchangeability, repeatability, tensile strength, temperature, and plug-in times of optical fiber connectors must also be considered.
(1) Optical performance:
The requirements for optical performance of optical fiber connectors are mainly the two most basic parameters of insertion loss and return loss.
Insertion loss (InserTIonLoss) is the connection loss, which refers to the loss of the effective optical power of the link caused by the introduction of the connector. The smaller the insertion loss, the better, and the general requirement should be no more than 0.5dB.
Return Loss (ReturnLoss, ReflecTIonLoss) refers to the ability of the connector to suppress the reflection of link optical power, and its typical value should not be less than 25dB. In the actual connector, the pin surface has been specially polished, which can make the return loss greater, generally not less than 45dB.
(2) Interchangeability and repeatability
Optical fiber connectors are universal passive devices. For the same type of optical fiber connectors, they can generally be used in any combination and can be used repeatedly. The additional loss introduced by this is generally less than 0.2dB.
(3) Tensile strength
For a finished fiber optic connector, it is generally required that its tensile strength should not be less than 90N.
Generally, the optical fiber connector must be able to be used normally under the temperature of -40oC~+70oC.
(5) Mating times
The optical fiber connectors currently in use can generally be plugged and unplugged more than 1,000 times.
Label interpretation: In the label indicating the pigtail connector, we can often see "FC/PC", "SC/PC", etc., which have the following meanings:
The part in front of "/" indicates the connector model of the pigtail, and the description is described above. "/" indicates the cross-section process of the optical fiber connector, that is, the grinding method. There are three types of fiber connector end-face contact: PC, UPC, and APC. <Figure omitted> PC——Physic Contact, the original meaning is the meaning of physical contact, the end face of the pin body is the physical end face; UPC——Ultra Physical Contact, the end face of the pin body is the super physical end face; APC type——Angled Physical Contact, plug The end face of the needle body is the angle physical end face; the difference between the three is not only the physical difference, but also the return loss, that is, the reflection loss (performance) is different. PC<UPC<APC. There is no APC type for multimode fiber. "PC" is the most widely used in telecom operators' equipment, and its joint section is flat. The attenuation of "UPC" is smaller than that of "PC". It is generally used for equipment with special requirements. Some manufacturers use FC/UPC for internal jumpers of optical connection equipment, mainly to improve the equipment's own indicators. "APC" is mostly used in radio and television and early CATV systems. Because APC uses an inclined end face, it can improve the quality of the TV signal. The main reason is that the TV signal is analog light modulation. When the connector coupling surface is vertical, the reflected light Return along the original path. Since the unevenness of the refractive index distribution of the fiber will return to the coupling surface again, although the energy is small at this time, the analog signal cannot completely eliminate the noise, so it is equivalent to superimposing a weak signal with time delay on the original clear signal. It is ghosting on the screen. The inclination of the pigtail headband prevents the reflected light from returning along the original path. Generally, digital signals do not have this problem.