TELEC started technical standards conformity certification and construction design certification services for 6GHz band of Wi-Fi 6E and 5.2GHz band wireless equipment in automobiles.TP-Link releases Wi-Fi 5 mesh system "Deco S7" for 8,000 yen per unit.Successor to the Deco M5Regarding Ethernet or 10GBASE-T, since 2017 [10GBASE-T, finally popular?], we delivered all 11 episodes and 2 extra episodes.However, twisted pair copper wiring Ethernet is up to 10GBASE-T, and 25/64GBASE-T has not yet been put into practical use.Regarding the first of these, "800Gbps/10km Reach SMF", from "Technical feasibility of the "10km @ 800Gb/s" objective" by Huawei's Tingting ZHANG/Sen ZHANG/Yan ZHUANG.Mr. 3 said, ``200G serial or 800G WDM, which one can achieve 1 million port shipments first?At the meeting in July, which was introduced in the previous article, a presentation titled "Considerations on the "10km @ 800Gb/s" objective was given, and it looks a little more advanced than this.Looking at the slide below comparing this area, if CWDM8 is left as it is, the dispersion (dispersion) is -59.4 to 96.4 ps/nm, which is quite large at 155.8 ps/nm.Even with the same CWDM, "400G-LR-6", which has CWDM4 and a reach of 6 km, is -35.6 to 20.1 ps/nm, and although the dispersion is relatively small with a total of 55.7 ps/nm, it is still 8 wavelengths and 10 km. , the increase in dispersion is unavoidable.This area can be suppressed to -50.8 to 9.4 ps/nm and a total of 60.2 ps/nm by using LWDM8 with narrower wavelength intervals.However, it is undeniable that dispersion will increase slightly, so it is necessary to take a little more power margin than 400G-LR4-6.Also, the problem with this method is that it requires twice as many ADC/DACs and transmitting/receiving elements compared to 400G-LR in order to transmit and receive eight pairs, and even if not twice as many DSPs. , the power consumption will increase as it is (this can also be doubled if it is made into DSP x 2 for 400G)."800G LR4" also has a dispersion of -59.4 to 33.4 ps/nm if CWDM4 is used, which is about 92.8 ps/nm.It's much better than 800G LR8 with CWDM8, but it's still pretty big.If this is also LWDM4, the dispersion will be -28.4 to 9.4 ps/nm and the total will be suppressed to about 37.8 ps/nm, which means that there is no problem with the characteristics.In addition, since only four pairs of ADC/DAC and transmitting and receiving elements are required, it is more feasible than 800G LR8 in terms of power consumption.However, compared to the same 200G x 4 "800G-FR4" with a reach of 2km, the dispersion is larger, so it is necessary to strengthen FEC compared to KP4.The third option, 800G LR1, which uses Coherent, has only one wavelength, so there is no need to consider dispersion. Not likely.As explained in "High bandwidth and low latency, reaching the limit of reach, four scenarios assumed by 800G Pluggable MSA", OIF has already developed the 800G Coherent communication method (probably "800ZR") at the end of 2020. This is because it seems that if the development of this progresses, it will be a realistic option to divert the component in this plan.The details are as explained in "Google seeks consideration of Coherent-Lite method for '800G-LR' with a transmission distance of 10 km". It is said that feasibility studies are being conducted.And the last is "800G LR4" using SHD.Regarding SHD, ``200G serial or 800G WDM, which one can achieve 1 million port shipments first?It is a derivative of the Coherent method.Since both ICR and SVDD are still being proposed as reception methods, it will probably be work that should be done within the Task Force in the future.However, this time, as an advantage of the SHD method, there was a more in-depth explanation about the feasibility.In the conventional method using IM-DD, only the signal strength can be restored, so there is a TDECQ penalty due to dispersion.However, when using SHD, there is no variance penalty.Also, the slight chromatic dispersion due to the edging wavelength in the O band can be corrected with a simple equalizer.Another advantage is that the configuration is simple.Calculating whether 10km is actually possible with 800G is still at the laboratory level, but we have already succeeded in transmitting and receiving 200Gbps per lane, 800Gbps in total, regardless of whether the receiving side is Receiver A or B. In addition, regardless of whether the light emitting element is DFB or ECL, basically the same transmission performance can be expected (left graph).Also, at OFC 2021, there was a paper about a 40km transmission distance, and even if it is 40km, it is said that signal transmission is realistically possible if an appropriate compensation mechanism is added (graph on the right), so at 10km The explanation here is that the feasibility is sufficiently high if there is (as an aside, the lead author of this paper is Mr. Sen ZHANG of Huawei, who is the second name in this proposal).By the way, when I read the paper, I used a light source with a wavelength of 1547.72 nm and used the Receiver B type as shown in the above slide of "Option 4 for 10 km @ 800 Gb/s (1/4)" as SOI. Built on the board and used.It is actually measured via a 40km optical fiber.This paper itself is a proposal for building an optical network of 800 Gbps to 1.6 Tbps rather than a demonstration for a specific standard, so for example, OIF is building a standard based on this. It seems not.In that sense, this paper can only be described as being verified at the laboratory level, but the Study Group has decided that this is sufficient.By the way, as a derivative of "800G LR4", which is the fourth proposal, a method of doubling the symbol rate while using SHD has also been proposed.However, is this SHD capable of 116GBaud?It seems to raise another issue.Freelance technical writer.His expertise spans a wide range of fields, from CPUs, memories, and chipsets to communications, OS, databases, and medical-related fields.Homepage is http://www.yusuke-ohara.com/"ER8" aiming for a reach of 40km at 800G, adopting MZM and paralleling two DSPs for 400GCopyright ©2018 Impress Corporation.