check-if-caldera-forms-is-active.php

<?php
/**
* Check if Caldera Forms is active
*/
if( defined( 'CFCORE_VER' ){
  //Caldera Forms is active
}else{
    //Caldera Forms is not active
}

load-after-caldera-forms.php

<?php
add_action( 'caldera_forms_includes_complete', 'my_addon_init' );
function my_addon_init(){
  //start your Caldera Form add-on code here, since Caldera Forms is loaded and Caldera Forms Autoloader is inititialized 
}