48 Keysight DFB Laser Source Module User’s Guide4 Cleaning InformationHow to clean connectorsCleaning connectors is difficult as the core diameter of a single-mode fiberis only about 9 mm. This generally means you cannot see streaks orscratches on the surface. To be certain of the condition of the surface ofyour connector and to check it after cleaning, you need a microscope.In the case of scratches, or of dust that has been burnt onto the surface ofthe connector, you may have no option but to polish the connector. Thisdepends on the degree of dirtiness, or the depth of the scratches. This is adifficult procedure and should only be performed by skilled personal, andas a last resort as it wears out your connector.To assess the projection of the emitted light beam you can use an infraredsensor card. Hold the card approximately 5 cm from the output of theconnector. The invisible emitted light is project onto the card and becomesvisible as a small circular spot.Preferred ProcedureUse the following procedure on most occasions:1 Clean the connector by rubbing a new, dry cotton-swab over thesurface using a small circular movement.2 Blow away any remaining lint with compressed air.WARNING Never look into the end of an optical cable that is connected to an activesource.
