Introduction to fibre patch leads
Here is a brief introduction to fibre patch leads, all the fibre patch leads mentioned below can be manufactured by anfkom.
Fibre patch leads are designed to rapidly and conveniently connect two fibre optic devices/equipment. With connector/connectors at either end, they enable a quick connection or disconnection of fibre optic cable. This way is much faster and easier than splicing. It provides a highly reliable way to transmit signals and is very popular in the telecom industry, especially for indoor applications, such as for easy installation when paired with patch panels, optical switches, and/or telco equipment. Sometimes it is used in an outdoor application, where requires the fibre patch lead has perfect waterproof performance.
Fibre patch leads are classified by transmission distance(long (Single-mode)or short distance(Multimode)), by connector type, by polish type(PC or APC). Different types have different colors for easy identification. The jacket of the single-mode fibre is normally yellow while the multimode fibre is normally orange (OM1 or OM2), Aqua (OM3) or Violet (OM4) (although we can make them in other colours). Connector colour Blue means PC while Green means APC.
Single Mode: It means the fiber enables one type of light mode to be propagated at a time; We also use 9/125 to indicate single mode, 9/125 means the fiber core diameter is 9um and clading is 125um.
Multimode: It means the fiber can propagate multiple modes. we also use 62.5/125, or 50/125 to indicate multimode. 62.5/125 or 50/125 means fiber core is 62.5um or 50um; OM1->OM2->OM3->OM4 is the road of continuous improvement of multimode fiber performance. The difference of OM1,OM2,OM3,OM4.
Polish type: PC, UPC and APC
PC (Physical Contact).The two end faces are polished to be slightly curved or microspherical, and the fiber core is at the highest point of the bending. This eliminates the air gap and forces the fibers into physical contact.
UPC (Ultra Physical Contact) is based on the PC to optimize the end face polishing and surface finish, the end face looks more dome-shaped. The end face of the UPC connector is not entirely flat, and there is a slight arc to achieve more accurate connecting.
APC(Angled Physical Contact). The end face of APC is usually polishing into an 8-degree angle. The 8° angled bevel makes the fiber end face tighter and reflects light through its beveled angle to the cladding instead of returning directly to the source, providing better connection performance.
Hence when to buy/choose a fibre patch lead, must make this information clear, single-mode(G652, G657) or multimode(OM1, OM2, OM3, OM4, OM5), connector type(SC, LC, ST, FC…), polish type(PC or APC). All this information are chosen according to the individual application. Fibre patch leads can be terminated with the same connector type or different connector types at both ends.
Most of the fiber patch leads are simplex or duplex. But sometimes multi cores fiber patch leads are required in some applications. Such as 8 cores, 16cores, … 96 cores.
In high-density applications such as data center. Tracing the link is a troublesome problem. Fiber patch leads with tracing function are developed to solve the problem, it make the tracing become easy and convenient.
Fibre patch leads also can used in the outdoor applications, such as FTTA applications. In this case, waterproof connectors must be used. ODVA, PDLC, Fullaxs waterproof connectors are widely used in the telecom industry.
The key parameters of fiber patch leads are insert loss and return loss, which is most rely on the connector performance. The loss that occurs while a signal is traveling through a component or system is called as Insertion Loss.Return loss is the loss of power in the signal returned/reflected by a discontinuity in a transmission line or optical fiber.
Usually we make the the Insertion loss<0.3db(single mode) or <0.2db(Multimode); According to IEC, there are 4 grades for Insertion loss and return loss:
|Return loss grade||Return loss(mated)||Notes|
|1||≥60dB||≥55dB in unmated condition(APC only)|
The key part of the connector is the ferrule, it plays an important role in controlling the insert loss and return loss. APC polishing should be chosen when the fibre link requires low return loss.