To get lighter steering you'll have to reduce the trail of your front end. You can do that by using a new fork with more rake. I don't know if such a fork can be found in carbon. To prove to yourself that trail is more important than weight, go ride an MTB with a suspended fork: in spite of having a fork that's 4 to 5 lb heavy you'll notice that the steering on them is quite nimble.

Besides, a good steel fork weight 2 lb: you'll gain, at the very most 1 lb for a fork that will be solid but more brittle if submitted to an impact. Moreover the steel forks remain more comfortable on rough roads: carbon is good at dampening small amplitude vibrations but it is quite rigid and big bumps are transmitted quite readily into the hands up to the shoulders at speed.