Written by 

Rohit Kunjappa

Head of Product Management & Application Engineering

Everything is growing in mobile network development – the size of test labs; the distance between radios and user devices; the number of devices that need to be connected; the number of topology changes. The world of connectivity has changed and continues to change at an ever-increasing pace.

One development contributing to this speeding up has been the development of modern laboratories. They have increased the pace at which new equipment can be certified as ready to deploy on a network. 

While older labs struggle to keep up with the demands for network function virtualization (NFV) and software defined networking (SDN), modern labs utilise fast, repeatable and agile lab operations to get new services to market much faster, and at a much lower cost. The longer it takes to certify new equipment and new services by relying on manual lab operations, the further away companies get from their business goals. Modern automated labs have an efficient and immediate method to cross-connect any network component within seconds, not hours or days. 

Switching switches

All-optical switches – such as the POLATIS solutions provided by HUBER+SUHNER – support a transparent, user-configurable fiber layer, independent of the traffic format or bit rate. This flexibility allows customers to rapidly reconfigure network test beds in seconds to meet the increasing demands placed on today’s test labs. All-optical switching automates the fiber interconnections, enabling remote configuration and testing at anytime from anywhere in the world. By cabling just once, the lab results are not subjected to potential fiber hygiene issues, creating a repeatable and reliable result. 

The switch should be as transparent as possible to deliver the most accurate test results, sized properly to interconnect all network elements within the lab today, and In the future.

Using intuitive web-based management software, tests can be scheduled, set up and run 24x7. The switch should therefore be fully compatible with the leading test automation software packages. 

Working with test automation software, the switch provides partitioned testing environments, which allow multiple groups within a company to run testing simultaneously, saving time and money. 

All-optical switches must be transparent to any and all bit rates, signal formats and protocols, so that as line rates and transmission formats continue to advance, the investment is preserved. This requires a high-performance, all-optical switch with ultra-stable operation as well as low back reflections and low insertion loss. POLATIS all-optical switches provide the superior specifications and features required for this application, including:

  • lowest insertion loss – Less than 1 dB optical insertion loss minimises signal impairment
  • unmatched performance – The only all-optical matrix switch with virtually no jitter and very low return loss
  • ultra-low cross talk – Better than -55 dB isolation between channels
  • broad range of matrix sizes – Unparalleled choice of symmetric and custom configurable port configurations for any size deployment.

However, an all-optical switch does not have to be used exclusively in a test lab where optical devices are under test. With the addition of an Radio Frequency over Fiber (RFoF) system you can also test RF devices.

The impact of 5G

5G is forcing wireless providers and equipment manufacturers to scale up their testing as a large number of devices have to be connected to radios. Traditionally, this would have been accomplished using coax cables and RF switches. The analogue nature of RFoF requires a switching infrastructure that does not degrade the RF signal. Using all-optical fiber cross-connects in place of RF switches can help telecoms providers to scale up and improve the quality of their testing. 

RFoF using all-optical switching addresses some key challenges:

  • with fiber, transmission over a distance is not a limitation compared with coax; 
  • more devices can be connected
  • fiber is less expensive than coax cables; 
  • topologies can be reconfigured at-will and remotely
  • fiber runs in test chambers do not interfere with anechoic chamber performance
  • creates a future proof signal distribution architecture – able to switch any RF frequency now and in the future.
  • the cost of all-optical fiber switches does not increase exponentially with port count 

An automated lab with an all-optical switch is a strong and worthwhile investment for those that are keen to ensure they are future ready and want to keep up with the demand which 5G and other technological developments are creating within the industry. With the addition of an RFoF system, the ability to also test RF devices only serves to increase the commercial viability of the test lab.