A family of Étale coverings of the affine line

It this note we prove the following theorem. Let Π^alg₁(A¹_C) be the algebraic fundamental group of the affine line over C, where C is the completion of the algebraic closure of F_q((1/T)), and F_q is a field with q elements. If F_q has at least four elements, then we show that there is a continuous surjection Π^alg₁(A¹_C) → _←lim SL₂(A/I)/{+ ± 1}, where A = F_q[T] and the inverse limit is over the family of non-zero, proper ideals of A. This result is proved by using the moduli of Drinfel'd A-modules of rank two over C with I-level structures; these curves give (tamely) ramified covers of the line and the tame ramification is removed using a variant of Abhyankar's lemma.