10G to 40G / 100G MPO Optical Link Testing Technology
Technology changes the life, informatization is the trend of the development of the world today. Networking, cloud computing, large data and other emerging network information technology innovation and application, and in mobile interconnection technology, the 3G network is maturing, 4G LTE network from the beginning of last year in the national pilot run, mobile interconnection speed will be a new step. In this era of information industrialization, we work and live in the city is also in the transformation of the Intelligent city, a variety of network applications are closely related to us. Whether it is the application of new technology or the construction of the Intelligent city, the application cannot be separated from the basic network. The construction of the basic network is based on the site, the active terminals, and interconnecting devices, as well as the basic interconnection channel-cabling system. Cabling system needs to be installed on the site, easy to be affected by environment, product quality, installation process and other factors, is the most important link to determine the quality of network transmission. The reliability of Cabling system depends not only on the quality supervision in the project but also on the final field acceptance test.
The urgency of test technology development
At present, most of the small and medium-sized cabling projects still use 10 Gigabit as the backbone to achieving Gigabit to the desktop network architecture. However, with the rapid development of 3G / 4G and Internet services, bandwidth cannot meet the needs of applications. The main link uses 40G / 100G to become a large-scale wiring project, especially the inevitable trend of enterprise data center and Internet IDC data center project construction. According to IDC market report, after 2015, 40G / 100G will gradually become the mainstream port rate.
Since the IEEE released the 802.3ba 40G / 100G standard in June 2010, the 40G / 100G network has mainly been based on experimental networks and has fewer requirements for on-site testing. After more than two years of systematic research and development testing, the current 40G / 100G transmission technology is maturing, major manufacturers have introduced 40G / 100G switching routing equipment, carrier-class long-distance backbone link using single-mode optical fiber systems, and buildings and data centers The integrated cabling system is mainly based on multimode OM3 / OM4 optical fiber system transmitting over short distances. It adopts 12-pin MPO connector and four-channel / ten-channel pre-connected optical cable. Pre-connected optical cable greatly reduces installation time and labor costs, but how to quickly identify the polarity of the fiber, fast and accurate test of the link attenuation has become the primary problem of field testing.
Traditional optical fiber testing technology
First of all, let us first review the original Gigabit, 10 Gigabit optical fiber link test technology. In 2003, TIA-526-14-A multi-mode optical cable installation light intensity loss test standard formally defines the CPR (CoupledPowerRatio) optical coupling rate detection method, the light source is divided into five levels (as shown below), LED light source is level 1 Light source, VCSEL The vertical cavity surface emits a laser light source at a level between level 3 and level 4, and the FP laser light source corresponds to a level 5 light source. At the same time, the test limits of optical loss are further increased. The maximum loss value of 1000BASE-SX applied to OM1 optical fiber is 2.6dB. The maximum loss value of 10GBASE-SR applied to optical fiber OM3 is 2.6dB. This standard, as a common standard for optical fiber link testing, is not aimed at specific network applications. It emphasizes the normal state of optical signal transmission. It is recommended to use LED light sources to test multimode fiber links. This method can detect the worst fiber link Happening. The laser-optimized VCSEL light source is used to detect the link for a specific network application. For example, if the active device uses a VCSEL light source or the current network is to be upgraded to use a VCSEL light source, the measured fiber loss value is relatively close to the real loss in the network application value.
850NM CPR Categories
The TIA-526-14-A standard is referenced by several related test standards such as ANSI / TIA / EIA-568-B, ISO / IEC11801, ISO / IEC14763-3 and others. And ANSI / TIA / EIA568-B.1.7.1 and ISO / IEC14763-36.22 also specify the size and use of 50 / 62.5um multimode fiber spools. The reel is modeled as a mode filter by means of a coiled optical fiber to reduce the high mode generated by the light source in the optical cable and reduce the difference of test results caused by different light sources and improve the stability and repeatability of multimode optical fiber testing.
10G MPO multi-core fiber test solution
Compared with traditional dual-core fiber optic connectors such as LC, SC, and ST, MPO connectors can support at least 12-core optical fibers. The MPO connector is mainly used for pre-attached optical fiber cables. Because MPO optic fiber has 12 core channels, TIA-568-C.0-2009B.4 has analyzed the channel polarity in detail, for the duplex transmission, there are mainly three kinds of polarities A, B, C connections. All three methods are for a common goal —- to create an end to end optical transceiver channel, but the three ways cannot be compatible, respectively, using different polarity connectors and adapters. For the entire link compatibility and consistency, as far as possible to consider the use of the same polarity connectors and adapters, such as the use of the jumper polarity are AB, adapter types are KEYUP-KEYUP, or the polarity will cause different Confusion, easy to install error, resulting in link failure. Therefore, in the 10G Fiber Channel, the MPO main link polarity mainly adopts Class C (see below). The two ports are internally interoperable according to the corresponding numbers. The optical channels are connected in groups of two or more, such as 1- – 2, 2 — 1, forming a full-duplex transceiver channel. The left and right ends are converted into the LC interface through the MPO to LC module box and then connected to the device through the LC jumper. This situation is mainly used in the data center high-density cabling system.
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