Low differential group delay (DGD) between the modes of a graded-index few-mode fiber is obtained by combining segments with DGD of opposite sign. Transmission of mode-multiplexed 620-GBd QPSK over a record distance of 1200 km is demonstrated.

Objects with unique 3D aspects can make identifying surface defects with standard machine vision configurations more difficult. One solution to achieve feature-appropriate surface contrast is Photometric Stereo.

5G deployments are now underway across the globe but are merely the first steps in a multi-year journey for the mobile industry. Many practical challenges still remain, not least of which is the challenge of cost-effectively deploying 5G Radio Access Networks (RANs) at scale and assuring the performance of supported 5G services.

The 5G RAN architecture provides an open, virtual, packet-based network that extendsfrom the core to the radio antenna. The virtual architecture of 5G RAN with network slicing and new functional elements, such as the Central Unit (CU) and Distributed Unit (DU), enables multiple demanding services to share the same infrastructure without compromising on their specific performance requirements. Virtual, packet-based RANs also enable network sharing over open interfaces as well as multi-vendor implementations, both of which are important to the 5G business case.

Hardware appliances, such as the Remote Radio Head and Baseband Unit of 4G LTE are now replaced with virtual software running on whitebox or Commercial Off-The-Shelf (COTS) hardware. In 5G, the Baseband Unit is split into two new functions, namely the CU and DU. Both these functions can be located either close to the 5G core or close to the Radio Unit (RU) to meet latency and backhaul requirements. This leads to a much more dynamic fronthaul, midhaul and backhaul network, which is now collectively referred to as the 5G cross-haul or “X-haul” network.

It also means that the traditional aggregation architecture where higher capacity is required closer to the core is no longer the norm. As cloud computing and other real-time services move closer to the edge of the network, more traffic is likely to remain close to the subscriber requiring higher capacity X-haul networks with 10G, 25G and even 100G Ethernet connectivity.

The flexibility and dynamic nature of 5G RANs poses new challenges for mobile solution vendors, network operators and service providers. One of those challenges is assuring performance in a highly dynamic environment. Traditional functional, application, integration and protocol testing can be used to test whether 5G equipment is implemented properly and performs as expected. However, these tests are not designed to determine how resilient or robust the equipment will be in the face of network issues that are common in Ethernet networks. 5G RAN packet networks are dynamic with many network configuration possibilities that can change instantaneously. There is, therefore, an additional need to test the limits of network equipment performance under various conditions to ensure dynamic changes in the Ethernet packet network do not lead to service performance issues or outages.

In other words, there is a need to plot the “performance landscape” of the 5G RAN, contouring the performance limits of network equipment and software functions and the 5G RAN itself. Network emulation of the Ethernet-based 5G RAN packet network with impairment testing can be used to stress test network equipment and virtual software in various configurations. This enables vendors to assure performance of their network equipment and software before delivery to network operators. It also enables network operators and service providers to plot their 5G RAN performance landscape at a fraction of the current cost and time and with greater accuracy. This is because testing can now be performed in the lab where a broad variety of scenarios can be tested that are often difficult, if not impossible, to perform in the field.

The oscilloscope has been a primary tool for electronic design engineers since the invention of that instrument, many years ago. The first decades of oscilloscopes were “analog” in nature.

Technologies and design considerations are presented for the design of very high bandwidth oscilloscopes. These include chip, DSP and microwave technologies employed in some of the fastest waveform digitizers in the world.

We experimentally demonstrate multiple-input-multiple-output transmission of a combined 3-space-, and 2-polarization-, and 5-wavelength-division multiplex in a 3-core microstructured fiber over 4200 km. This is the record transmission distance for spatial-division multiplexing in a fiber.

We transmit 32 WDM channels over 12 spatial and polarization modes of 177 km few-mode fiber at a record spectral efficiency of 32 bit/s/Hz. The transmitted signals are strongly coupled and recovered using 12 x 12 multiple-input multiple-output digital signal processing.

Companies manufacturing all sorts of products use Quality assurance (QA) to prevent errors and mistakes in their products and ensure flawless product deliveries to their customers. This willimprovecustomer satisfaction and reducethe need for after-salestroubleshooting and support.

QA give companies get a systematic process to find outif their products meet what is required. QA defines requirements for developing and manufacturing reliable products.A driving force behind QA is the ISO(International Organization for Standardization). ISOhas developed the ISO 9000international standard, on which many companies base their QA system.

QA testing is done during and after development andprovidesinformationtodevelopers if changes or improvements are required.During product development the development team will do thorough testing of the product, covering e.g. functional and stress testing of the basic functionality of the product. QA testing of physical products normally includes stress testing of a number of environmental conditions.QA tests that may be conducted include:

• EMC Tests •Mechanical Tests
• Thermal/Humidity Tests
• Hi-Pot Tests
• Sand and Dust Tests
• Salt Spray Tests

Networking devices supporting 800Gbps Ethernet are now being developed, with some industry analysts predicting the next tech cycle of 1.6Tbps (Terabits per second) could arrive as early as 2024.

But the devil's in the details - and there are a lot of details.

Xena's new White Paper examines the technical options and challenges of bringing terabit Ethernet to life. Learn how faster electrical lane speeds, new modulation schemes and the need for better Forward Error Correction (FEC) mechanisms are playing a key role, as well as why you'll need to test changes to the Ethernet physical layer and transceiver form factors.

A single-polarization 160-Gb/s (80-Gbaud) electronically time-division-multiplexed (ETDM) quadrature phase-shift-keyed (QPSK) signal is generated and coherently detected using two 45-GHz-bandwidth oscilloscope prototypes and offline processing.