  In the present paper, we show that if the dimension of an arbitrary algebraic
geometry code over a finite field of even characters is slightly less than half
of its length, then it is equivalent to an Euclidean self-orthogonal code.
However, in the literatures, a strong contrition about existence of certain
differential is required to obtain such a result. We also show a similar result
on Hermitian self-orthogonal algebraic geometry codes. As a consequence, we can
apply our result to quantum codes and obtain quantum codes with good asymptotic
bounds.
