A threat detection system receives links from emails opened in web browsers. Each attachment has a connector connectable to the electronic circuit to be controlled, and a memory accessible by the controller that contains configuration data for accessing the electronic circuit, and operational software for operating the electronic circuit. The tester also has force measurement means to measure the tension so imparted and displacement measuring means to measure the displacement of the fabric. The inner core region is doped with a rare-earth element, such as Er2O3, and a co-dopant, such as Al2O3, and the outer core region is doped with a dopant such as GeO2.