Herbert Scott Gallop, 53, from Forres, was found guilty of molesting the victim despite repeated requests to desist.
The offence occurred in 2017 and left the woman confused and upset.
Gallop, an RAF veteran who went on to have almost 20 years police service, retired from the force after the allegations against him were officially investigated.
At Elgin Sheriff Court today (10 Nov) he was given a one-year Community Payback and his name was added to the Sex Offenders Register for one year.
Commenting on sentence, Andy Shanks, Procurator Fiscal for Grampian, Highland and Islands, said:
“Herbert Scott Gallop was a respected police officer who knew he was abusing his position of trust.
“It took courage for the victim to speak out against a figure of some authority and I would commend her determination to seek justice.
“The Crown Office and Procurator Fiscal Service will use all tools at its disposal to ensure offenders face the consequences of their behaviour.”