We investigated the conditions that cause a connector damage during a high-power transmission in an optical connector with house dust on its endface. In this paper, to examine the connector conditions that cause the connector damage, we focused on optical characteristics, such as insertion loss and return loss, dust attachment pattern, and optical power. We show the relationship between the connector damage and the MFD of the fiber used in telecommunication network when house dust is used as a contaminant. Moreover, we show the threshold value of the input power level needed for damage to occur to a connector with house dust on its endface when that power is interrupted completely. We also describe the operating procedure for a secure high-power transmission, where the procedure consists of connector cleaning, connector endface observation, and insertion and return loss measurements. We show that it becomes possible to completely remove dust, which we could not remove with a cleaner alone, by using an air duster in combination with a cleaner. We also show that an optical connector cleaned with our proposed procedure, which exhibited an insertion loss of less than 0.5 dB and a return loss exceeding 45 dB, tolerated a high optical power of 5 W.
