Understanding how loss affects an LR4 QSFP and it might not reach the maximum 10km indicated.
Loss in optical fiber communications refers to the reduction in optical power of a signal as it travels through an optical fiber. The reach of a 100G LR4 QSFP (Quad Small Form-factor Pluggable), which is a high-speed optical transceiver used for data transmission over optical fibers, is affected by loss in a number of ways.
The primary cause of loss in optical fibers is absorption and scattering of light. Absorption occurs when light energy is absorbed by impurities in the optical fiber core, while scattering occurs when light energy is scattered in all directions by fluctuations in the refractive index of the fiber core. These processes cause the light to be absorbed or scattered into directions other than the fiber core, resulting in loss of the optical power of the signal.
In addition to absorption and scattering, the reach of a 100G LR4 QSFP is also affected by bending loss. This occurs when the optical fiber is bent, causing the light to be refracted and scattered in all directions, reducing the optical power of the signal. The amount of bending loss depends on the radius of curvature of the bend, with smaller radii resulting in greater loss.
The reach of a 100G LR4 QSFP is also affected by connector loss. This occurs when the optical signal passes through a connector, such as a splice or a connector interface, causing some of the light to be lost. Connector loss is a function of the quality of the connector and the insertion loss, which is the loss that occurs when the connector is inserted into the optical fiber. Each connection and/or device will add to the loss.
The reach of a 100G LR4 QSFP is also affected by dispersion, which is the spreading of the optical signal in time and wavelength. There are two types of dispersion that affect the reach of a 100G LR4 QSFP: modal dispersion and chromatic dispersion. Modal dispersion occurs in multi-mode fibers and results from differences in the arrival time of the different modes of the signal, while chromatic dispersion occurs in single-mode fibers and results from the different wavelengths of light having different phase velocities.
Another factor that affects the reach of a 100G LR4 QSFP is the receiver sensitivity. The receiver sensitivity is a measure of the minimum optical power required for the receiver to detect the signal. The reach of a 100G LR4 QSFP is limited by the receiver sensitivity, as the optical power of the signal decreases with distance, it becomes more difficult for the receiver to detect the signal.
In conclusion, the reach of a 100G LR4 QSFP is affected by a number of factors, including loss due to absorption, scattering, bending, connector loss, dispersion, and receiver sensitivity. To maximize the reach of a 100G LR4 QSFP, it is important to minimize these factors and to use high-quality optical fibers and components.
Fibrenet have an extended reach LR4 option capable of 20km at a slight increase of cost over the standard 10km LR4 – with compatibility available for nearly all vendors. Please call us for details and we will provide pricing and availability. If you would like to speak to one of our team, please call today on 01666 715 715 or contact us here and our knowledgeable sales team will be able to assist you. As always, please get in touch if we can help explain anything or products you may require are not listed online.