To avoid unwanted scatter from stray light, it is necessary to assemble ferrules with free-standing fibres by using a shorter ferrule. This allows any misdirected light that does not couple into the fibre to pass outside the ferrule and is effectively ‘beam dumped’ into the void surrounding the ferrule within the connector package.
One quality criterion in such assemblies is the centricity of the fibre core to the ferrule’s outer diameter. This plays a particularly important role in connectors without a keyway, like those used in polarisation maintaining fibres. According to Laser Components, a centricity of under 10µm is achieved in its production process, allowing assembled cables in field applications to be changed without any adjustment. To reduce the amount of reflections at the air/glass interface, fibre end faces can be coated by request. The transmission of AR-coated fibres is improved by 3.5 to 4% per face.