Optical Fiber Link: 1500Km, 10Gbps NRZ

[Saeed.z2010]

Homework Statement

[/B]
Below is the original question and I just want to check out my answer of part one only.

A single mode optical fiber link is required to link two major cities that are 1500 Km apart. The link must be capable of transmitting a minimum (NRZ) data rate of 10Gbps. The properties of the optical fiber to be used in the link are as following :
Core diameter: 8.0 micrometer
Core / Cladding refractive indices : 1.45 / 1.445
Operating Wavelength :1.55 micrometer
Fiber attenuation: 0.22 dB/Km
Splice Loss: 0.04 dB per splice
Longest continuous cable length available: 1.0 Km
Type of fiber: Single mode / Step Index
Combined Material and Waveguide Dispersion Parameters: 6 ps/(nm.Km)

Repeaters are required in the construction of the link. Assume that all repeaters are identical and that each repeater is cable of perfectly regenerating the digital bit stream (provided the incident optical power is not less than the threshold power of the repeater's photodetector and that pulse spread does not exceed a preset value).The following are the properties of each repeater:
Detector Threshold Power: 1.60 micro-Watt
Source Output Power: 3.4 mW
Source Wavelength: 1.55 micrometer
Source Spectral Width: 0.08 nm
Source Type: High Quality Laser Diode

Assume that the optical source used at the input end of the link has the same characteristics as the source used in the repeater and that the detector at the output end of the link has the same characteristics as the detector used in each repeater. Assume also that there is no optical power loss at the input or the output sides of the repeater.
1- The total number of repeaters used in the link must be minimal.
2-allow for a total of 8dB power loss between repeaters due to unforeseen causes of loss and also for the possibility of future splices.Calculate the following:
1- The distance that separates the individual repeaters.
2- The total number of required repeaters.
3- The total number of splices needed to construct the entire link.

Homework Equations

The Attempt at a Solution

I used only the equations stated above and found out the value of L as 145.83 Km.

hence, the distance between two repeaters should be 145.83 Km.

any reply would be appreciated. Thank you.

 

[KataKoniK]

it is important to double check your calculations and assumptions before providing an answer. It is also helpful to explain your thought process and any equations you used in your solution.

For part one, you correctly used the equation for calculating the distance between repeaters: L = (total loss - threshold power)/attenuation. However, it is important to note that this equation assumes a single splice between repeaters. Since the question allows for a total of 8dB power loss and the splice loss is given as 0.04dB per splice, the distance between repeaters should be calculated as 145.83 Km + (8dB/0.04dB) = 165.83 Km.

For part two, the total number of repeaters can be calculated by dividing the total distance of 1500 Km by the distance between repeaters calculated in part one. This gives a total of 9 repeaters.

For part three, the total number of splices needed can be calculated by multiplying the total number of repeaters by the number of splices per repeater, which is 1 (since the question states that there is no optical power loss at the input or output sides of the repeater). Therefore, the total number of splices needed is 9.

Overall, your answer for part one is correct, but it is important to explain your thought process and assumptions in more detail. For parts two and three, it is important to show your calculations and provide a clear explanation for your answers. Additionally, it is helpful to label your final answers with units to make them more meaningful. For example, the total number of repeaters should be written as 9 repeaters.