Abstract: An optical card (1) comprising a surface protection sheet (4) laid on the surface (2a) of a core sheet (2) through a surface side adhesive layer (3) functioning as a surface-side clad layer, and a back surface protection sheet (6) laid on the back surface (2b) through a back surface side adhesive layer (5) functioning as a back surface-side clad layer, wherein a large number of V-grooves (7) are made, at a constant interval, in the surface (2a) of the core sheet (2) and the opposite ends (7a, 7b) of each V-groove are exposed to the end faces (2c,2d) of the sheet. Sectional parts (8(2), 8(4), . . . ) of the core sheet (2) formed between respective grooves (7) function as optical waveguides and remaining sectional parts (8(1), 8(3), . . . ) each provided with a V-groove (light shielding groove) (9) extending across adjacent V-grooves (7), function as non-optical waveguides.

Abstract: In an optical fiber array (1) which has a V-groove substrate (2) formed in its surface (2a) with V-grooves (3) for arranging optical fibers, a plurality of optical fiber cores (61) fixedly bonded in each individual V-groove (3) of the V-groove substrate (2), and a pressure plate (4) fixedly bonded to surfaces of the optical fiber cores (61), an adhesive comprising a resin composition (component A) having an OH group after curing and a filler (component B) is used to fixedly bond the V-groove substrate (2), the optical fiber cores (61), and the pressure plate (4). This adhesive has a glass transition temperature that is somewhat lower than the ambient test temperature and possesses somewhat higher elasticity. Therefore, large internal stress does not occur in the adhesive even under conditions of high temperature and high humidity. Consequently, no peeling occurs as a result of moisture penetration since gaps cannot form between the pressure plate (4) and the adhesive.