We extend the “hundred”
As the demand for bandwidth increases, network owners are getting worried. How to handle 100Gbps transmission over longer distances?
Of course we have at our disposal DWDM systems (“What is DWDM”), which will cope with it without any problem, both at short distances (“QSFP28 DWDM”)as well as at longer distances (“Understanding Coherent Transmission”). But what if only one 100G transmission is enough and we don't want to invest in building a DWDM system?
Wanting to build 100G transmission at a distance of several or a dozen kilometers, we can use for this purpose 100G LR4 insert. The most popular format is the QSFP28 version.
This module on the optical side sends a signal in 4 wavelengths: 1295.56, 1300.05, 1304.58 and 1309,14 nm. Thus, in the interior of the insert, a corresponding multiplexer is built in on the transmitting side, and on the receiving side - a demultiplexer.
Power budget QSFP28 LR4 inserts are usually a few decibels. As we combine this with the fact that the transmission takes place in the second optical window, where the insertion losses are 0.35 dB per 1 km of fiber, obtaining greater distances of the inserts begins to be problematic.
An additional difficulty is the fact that the standard clearly defines the value maximum power consumption of the cartridge, which is 4.5 IN. So how to cope with the transmission of a single “hundred” over a long distance? Can we somehow amplify this signal?
The answer to the last question is: SODA. Semiconductor Optical Amplifier is a semiconductor optical amplifier. It works very much like a laser. It consists of two specially designed semiconductor wafers and a layer of other material between them, forming the so-called active layer. The fundamental difference from the laser is the absence of internal light reflections.
In the case of an amplifier, we want the signal to be input inside, amplified and output to the outside. The second difference is that in the case of a laser we want to emit light of only one specific wavelength, while we expect the amplifier to amplify the largest possible wavelength range.
This is because if we want to amplify the signal coming from, for example, the QSFP28 LR4 insert, we need to amplify 4 wavelengths simultaneously. Therefore, we have insert generating 4 wavelengths around 1310 nm, we have an amplifier, which is able to strengthen them all at once. So let's get to work!
How far do you need to transfer 100 Gbps? Is it 50 km or 100 km, or maybe even more? Feel free to contact us.
Remember that we are a helping hand for those companies whose functioning and efficiency depend on efficient networks. We help build good ICT networks!