Get php Data from Curl response

My php curl return this results:

[
    {
        "hd_profile_pic_url_info":{
            "height":320, 
            "width":320,
            "url":""
        },
        "highlight_reel_count":0,
        "bio_links":[],
        "is_new_to_instagram":false,
        "pronouns":[],
        "media_count":3,
        "is_professional":false,
        "is_business":false,
        "should_show_category":false,
        "should_show_public_contacts":false,
        "business_contact_method":"UNKNOWN",
        "has_guides":false,"external_lynx_url":"",
        "external_url":"",
        "mutual_followers_count":0,
        "biography":"I love being simple!!",
        "following_count":5,
        "follower_count":12,
        "is_verified":false,
        "profile_pic_url_hd":"",
        "profile_pic_url":"",
        "is_private":false,
        "full_name":"Fairy Tale",
        "username":"fairytalefolkdorset",
        "pk":"53136201590",
        "_type":2,
        "_r":1
    }
]

I want to get the "full_name" value:

$response = curl_exec($curl);
$err = curl_error($curl);
curl_close($curl);

$name = $response->full_name;

What code should i use?