Bradley Williams, 35, admitted recording and sharing intimate videos and photos of two girls aged 16 and under and a woman in her 20s, between 2014 and 2021.
He posted some of the photos on kink and fetish social networking site FetLife.
The now-former Victoria Police officer faced the County Court in Melbourne on Monday via video link from prison, where Judge Patricia Riddell said his offending was "reprehensible".
"To the outside world you were tasked with upholding the law, while behind the scenes you were recording and transmitting images of two teenage girls who were legally children," she said.
Williams met his 14-year-old victim online when he was 25 and began video chatting with her.
On her 15th birthday he took screen shots of her in various states of undress during a Skype call.
Seven years later, when she became engaged to her fiance, Williams sent her three sexual images he had taken of her when she was 15.
He also sent an explicit video of the girl to his friend, a prison officer named Ethan Flintoft, and posted images of her to FetLife.
He met his next victim when he was 32 and she was 16, beginning a sexual relationship with her.
Flintoft also had sex with the girl.
Williams took seven videos of their sexual encounters with the teen, where he called himself "daddy", a pedophile and told her to "shut the f*** up".
He sent three of these videos to his first victim via Snapchat, saying the girl was "damaged goods" and "really young, definitely under 18".
Williams also filmed a 28-year-old woman and shared it on FetLife without her permission.
She reported him to police because "someone like this does not have a right to have a job that he does".
Judge Riddell said Williams' offending was inherently serious as it involved the exploitation of vulnerable victims for his own sexual gratification.
She said it was particularly damaging for child victims to have their images posted online "which then exist for all time".
"Any victim will no doubt be concerned and anxious about the fact those images may be uncovered or shared again and again at any future time," she said.
"Once those images or videos are shared with others, a victim loses all control over where they may end up or when they may reappear in their adult lives."
She jailed Williams for up to four years and two months and he will be eligible for parole after serving two years of this sentence.
He will be registered for life as a serious sex offender.
Flintoft, who pleaded guilty to distributing and producing child abuse material, avoided jail and was handed a three-year community corrections order.
He must perform 250 hours of unpaid work and attend a sex offender program.
1800 RESPECT (1800 737 732)
National Sexual Abuse and Redress Support Service 1800 211 028
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