How to support long-distance fiber-optic applications

Three fiber types are commonly used in building cabling systems: 62.5/125 μM multi-mode optical fiber, 50/125 μm multi-mode optical fiber, and single-mode optical fiber. With the development of ipvimax SCS, a new 50/125 μm optical fiber optimized for low-cost 850nm laser application is applied in global cabling systems, this series has also been added to the standard.

The optical fiber that meets these basic types of requirements must meet the minimum performance level requirements. In a broad sense, the optical fiber must meet the performance requirements for bandwidth and attenuation. These application standards also define minimum performance standards for their transmitter and receiver, and provide robust specification requirements for combinations that meet the worst-case standards.

In consideration of these issues, users, consultants and installers should ask suppliers about the critical feature guarantees and support certificates for such optical fibers. Verification of these support may include multiple different "Proofs ". For multimode optical fibers, there is a "proof" of "Full bandwidth" or "high-limit mode loading (rml) bandwidth ". Another "proof" is that "they have tested multiple products ". All of these proofs are flawed.

Multi-mode optical fiber is a multi-path transmission medium. The bandwidth depends on the path (or mode) in which the signal is transmitted. The initial path is determined by the sender's activation conditions. Full bandwidth has a low load capacity for laser transmitters (typically used in applications over 155 Mb/s) because the activation conditions for these transmitters vary greatly, generally, there is no overflow condition. Rml bandwidth also suffers from the same problem. The conclusions drawn from the study of rml experiments are only applicable to 62.5 μm optical fibers and are valid only when used together with transmitters meeting specific activation conditions.

No application uses these enable conditions, and studies show that transmitters that do not meet the enable conditions are prevalent. Finally, the conclusions drawn from tests on a small number of optical fibers cannot prove that the manufacturer knows how to choose excellent performance.

Of course, some manufacturers also associate extended distance support with multimode optical fiber 1300 nm transceiver, such as 1000base-lx. As no 1300 nm source conditions are specified in any standard, multiple methods for producing such transmitters may form the activation of various multimode optical fibers.

Therefore, these claims must indicate various possibilities for spontaneous activation, or must rely on external conditions-for example, adjusting the strictly controlled enable mode of jumpers through expensive enable modes. In contrast to the 850 nm laser optimized multimode optical fiber, the Multimode Optical Fiber adopts the DMD control transmission feature and complies with the spontaneous activation conditions defined by the 850nm application.

However, the long-distance solution of multimode optical fiber in the 1300 nm window introduces another problem. Why do users need to install a new 1300 nm enhanced Multimode Optical Fiber to support 1000base-lx, while the 1000base-lx transceiver was originally produced for a single-mode optical fiber.

The reason why people use a Multimode solution to replace a single-mode is that the cost of the multimode solution is low, rather than the cost of optical fiber. In fact, the cost of a 850 nm multimode electronic instrument is much lower. This is why we need to use an optimized Multimode Optical Fiber for transmission at the 850 nm window.