The 20W Power Adapter that you illustrate appears to be entirely genuine.
If supplied with an iPad (the illustrated Power Adapter being supplied as standard with many new iPads in the UK/Eire), or if purchased as an accessory directly from Apple or an Apple Authorised Service Provider, you should have no cause for concern as to its provenance.
Here is another example of the same Apple 20W Power Adapter with which to compare…
