If you lost/deleted calendar on iPhone/iPad/iPod, you should read this post to restore/recover your calendar from your backup or iOS device directly.
Want to sync Outlook calendar with iPhone? This post will show you three ways of syncing Outlook calendar with iPhone, iTunes and iCloud for easy viewing on iPhone.
How to access iCloud from PC to view and manage iCloud calendar? This article gives you three simple methods to manage iCloud calendar on PC.