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Chromatic Dispersion
Optical Communication

Testing Transceivers for Chromatic Dispersion

On: Aug 28, 2023

In: Optical Communication

By: Marc-André Laliberté

One of the key challenges when testing transceivers and digital signal processing algorithms (DSP) for chromatic dispersion robustness is generating significant amounts of chromatic dispersion. While the most intuitive solution would be to use a transmission fiber setup, as it closely replicates field conditions, is this the most effective solution from a cost and performance standpoint?

TeraXion’s ClearSpectrum™ CDE is a fixed, entirely passive chromatic dispersion emulator that has been developed to test the dispersion robustness of transceivers and DSP over thousands of kilometers of transmission fiber.

Based on TeraXion’s reliable fiber Bragg grating technology, the CDE is significantly more cost-effective than a transmission fiber setup, it has a very low insertion loss and can emulate up to 45 000 ps/nm of dispersion in a very compact half 1U 19-inch rack module.

Suitable for Advanced Modulation Formats

Thanks to the different configurations offered, the CDE can be used to test a multitude of modulation formats, at different data rates.

The CDE has a proven track record in labs worldwide for testing the robustness of 100G/200G coherent DP-QPSK transceivers and DSP algorithms.

400G and 800G transceivers such as OSFP and QSFP-DD, are now tested for chromatic dispersion robustness, as per new established standards. Thanks to its wide bandwidth, the CDE can emulate dispersion at very high baud rates, including 136 Gbaud/s 800G signals.

A Highly Customizable Solution

One CDE, Many Configurations

The CDE can be used in most transmission applications, as it is offered in C-band and L-band configurations, and even an O-band configuration upon request.
The C-band and L-band CDEs are offered in a multi-channel profile for testing 100G-400G optical modules at multiple wavelengths at once, or in a very wide bandwidth single-channel profile for the latest and upcoming high data rate applications.

C-band Profile Examples

Massive Levels of Dispersion

While a single half 1U 19-inch module for C- or L-band can provide up to 45 000 ps/nm, it is possible to cascade multiple modules to reach massive levels of chromatic dispersion.

CDE vs Transmission Fiber

Save on the cost and space of fiber spools and EDFAs with a ClearSpectrum™ CDE.
Thanks to TeraXion’s FBG-based design, the CDE emulates the dispersion of thousands of kilometers of transmission fiber in a single compact module and with fewer EDFAs, driving the total cost of acquisition down. And the CDE is as convenient to use as it gets; just plug and play.

Up to 3x

Up to 10x


Learn more about TeraXion's Optical Communication Laser Components

Chromatic Dispersion Emulator