Verification report part 2! How far can you fly with Coherent's high-power version 400G-ZR?

Narrow down by specifying conditions

現在2149件がヒットしています。check

Base network module Coherent

Over the course of two installments in this series, we will explain the results of testing how many kilometers we can actually fly using Coherent's 400G-ZR/ZR+ optical transceiver module.

In the previous verification report, we verified with a 400G-ZR+ optical transceiver module. We have received a number of positive feedbacks from our customers, such as, "It's hard to do experiments on our own, so it's helpful," and "The results of actual experiments are easy to understand."

This time, as a sequel, we will introduce the verification results of the 400G-ZR, which does not have a "+" at the end.

Coherent's 400G-ZR, like the 400G-ZR+, is a high-power version with an output of 0 dBm, and when considering long-distance communication networks, it is possible to reduce the total cost by reducing the number of optical amplifiers. . Furthermore, the power consumption of the 400G-ZR product is 18.5W, which is lower than the power consumption of the 400G-ZR+.

First of all, I will briefly summarize the verification results using this 400G-ZR.

・When I checked one-to-one communication using 80km bare fiber, error-free communication was possible without an optical amplifier.

・When we added a variable optical attenuator to a 40km bare fiber and confirmed it, we found that it was possible to communicate error-free up to 48km in a dark fiber environment without an optical amplifier.

Now let's take a look at the detailed experimental results.

1. Can one-to-one communication be achieved over 80km of bare fiber?

The transmission and reception of Coherent's 400G-ZR optical transceiver module were looped back over 80km of bare fiber to confirm error-free communication.

1.1 Measurement system

The optical signal transmitted from the high power version 400G-ZR optical transceiver module returns to the reception of the optical transceiver module through 80km bare fiber. The loss for this 80km bare fiber is 15.6dB.

The high-power 400G-ZR optical transceiver module is mounted on Coherent's evaluation board, and this evaluation board is connected to a PC with a dedicated GUI installed via a USB cable.

With the GUI, you can control the optical signal transmitted from the optical transceiver module and analyze the received optical signal.

1.2 Measurement results

I looped back over 80km bare fiber and confirmed Post-FEC BER = 0.

1.3 Summary

We were able to confirm error-free communication with one-to-one communication using 80 km of bare fiber.

2. Is P2P communication possible over 40km of dark fiber?

We added a variable optical attenuator to 40 km of bare fiber to create an environment equivalent to dark fiber and verified how far we could fly.

2.1 Measurement system

The optical signal sent out from 400G-ZR passes through a 40km bare fiber and is further attenuated by a variable optical attenuator.

Assume that the attenuation of this variable optical attenuator is 12.2dB, and 20dB in combination with the 40km bare fiber. This resulted in a dark fiber environment of 0.5 dB per km.

2.2 Measurement results

Pre-FEC BER = 3.95E-03

Post-FEC BER = 0

In a dark fiber environment with a loss of 0.5dB per 1km, we were able to confirm that communication can be performed without any problems even if the fiber is flown 40km without an optical amplifier.

400G-ZR uses error correction called C-FEC, and the FEC limit is 1.25E-02, which is 0.0125.

The result of this measurement is that Pre-FEC BER = 3.95E-03 is 0.00395, so there is still a margin of about one digit relative to the FEC limit of 0.0125.

2.3 Summary

We were able to confirm error-free communication over 40 km of dark fiber. In addition, we found that there is still plenty of room to meet the FEC limit.

3. How many kilometers can P2P communication be possible with dark fiber?

Using the same system shown in Fig. 2 as before, we increased the value of the variable optical attenuator and verified how far error-free could be maintained.

3.1 Measurement results

The error-free limit was when the attenuation of the variable optical attenuator was 15.4 dB. The BER at that time is as follows.

Pre-FEC BER = 1.14E-2

Post-FEC BER = 0

The fiber loss is 7.8dB and the variable optical attenuator loss is 15.4dB, so the total is 23.2dB.

This is equivalent to 46 km, assuming a dark fiber loss of 0.5 dB per km.

3.2 Summary

It was found that it can fly up to 46 km in a dark fiber [*] environment.

[*] Assuming 0.5 dB per 1 km

Summary of this article

I have introduced several experiments to see how far you can fly with Coherent's high power version 400G-ZR.

We confirmed error-free communication in one-to-one communication using 80km bare fiber.

Also, an experiment with a variable optical attenuator added to a 40km bare fiber showed that it could fly 46km in a dark fiber environment.

Verification condition	Verification result of high power version 400G-ZR
Is it possible to fly 80km without an optical amplifier?	fly without problems
Is it possible to fly 40km with dark fiber without optical amplifier?	fly without problems
How far can you fly with dark fiber without an optical amplifier?	Can fly 46km

Inquiry

If you are considering 400G transmission over several tens of kilometers, please consider Coherent's high-power 400G-ZR/ZR+. Macnica can make proposals based on your own communication environment and the conditions you want to achieve. If you are having trouble with implementation or have any problems with optical transceiver modules, please contact us using the form below.