How to transfer data from the child window to the parent window?

I have two react components parent and child. I need to pass a token from a child component to a parent. The child component is opened with window.open from the parent component. I cannot get a reference to the parent component and pass data to it from the child.

function Parent() { 
return (
const SSOWindowOpen = () => {
const left = (screen.width - 465 ) / 2
const top = (screen.height - 650 ) / 4

const SSOWindow = window.open('/sso', 'SSOWindow',
'resizable=yes, width=' + 465
+ ', height=' + 650 + ', top='
+ top + ', left=' + left);)
}

child component

function children() {
return (
const Token = 123-token-123
window.opener ??????
)
}