| http://www.w3.org/ns/prov#value | - A may be formed in the area except the area facing the central part in the width direction (transverse direction) of the upper electrode layer 34.Due to the rib structure constructed by a concave portion 21A and a convex portion 22A, the concave portion 21A of a lower cladding layer 21 has a depth D.sub.2 and a width W.sub.2 which produce a change on an effective refractive indexdistribution in th
|
