Knowledge

Compare the dual-fiber bidirectional and single-fiber link modes, explain how the WDM transceiver uses a pair of wavelengths to achieve bidirectional communication on a fiber core, and list three engineering situations that are still recommended to retain dual-fiber.

Disassemble the fiber optic link budget in three steps: take the worst optical port parameters of the modules at both ends and convert the length to attenuation, account for the connector, fusion and aging allowances, and finally check the receiving allowance, and attach a complete calculation example of a 10-kilometer gigabit single-mode link.

Explain the relationship between dB, dBm and the three units of optical power, teach you to read the three numbers of transmit power, receiving sensitivity and overload point on the optical module label, and give the three-step operation of self-checking the link margin with an optical power meter.

Explain the division of labor between the three common wavelength windows of 850, 1310, and 1550 nanometers, explain why the long-haul link prefers 1550, and the dispersion cost it brings, and give the practical practice of pairing single-fiber bidirectional links by wavelength.

From the four dimensions of core diameter, dispersion, transmission distance and complete cost, it is said that the difference between the list mode and the multimode fiber helps to determine which type of optical module should be equipped when obtaining the optical cable or planning a new link, so as to avoid the situation of being able to connect at close range and using error bits for a long time.

The interconnection selection methods in three distance zones within the cabinet, across cabinets, and in the computer room are quantitatively compared with the single port cost, power consumption, and failure rate of the DAC/AOC/SR4/LR4 solution, and a selection table that can be directly applied is given.

The causes and countermeasures for the three most common pitfalls of fiber-optic monitoring points: difficulties in obtaining power, ground loop burnt ports, and roadside cable disconnections: the practical key points of integrated power supply for POE transceivers, optical port isolation, and armored jumpers.