Share iCloud Cal to Google Cal

I would like to share my Cal/iCloud Calendar to my wives Google Cal and probably the reverse as well, so i can see hers.

Firstly, sharing mine... i notice on my PC here [as i view my iCloud cal on a PC, on my Mac and IOS device.. and assume the settings will be roughly the same on all] i can:

share to another iCloud Cal

Create public link

if i create a public link and link my wives Google Cal to it, she will see my Cal, but as its 'Public', is there anywhere else people can pick up this calendar from? See it if i dont want them to? i do they have to receive the link from me to be able to see it? its not searchable on search engines or anything is it?