It's a steel fork, and my efforts have been fruitless to find a lighter one.
If it's any help here's an affordably priced 1-1/8" steerer carbon fork for 20" wheel I recently came across:
http://www.performer.com.tw/2010/use...p=05&sno=00334
max tire 451x1-1/8
Performer also makes another carbon fork 451x1.0 that they don't list on their site.