Optical fiber sheet

An optical fiber sheet comprising an optical fiber and a wire that are arranged between a first sheet and a second sheet,

• wherein the optical fiber is a multi-mode optical fiber having a core of silica glass to which a refractive index adjuster is added, has a numerical aperture equal to or less than 0.30 and a flexural rigidity equal to or less than 0.50 N·mm2, wherein the optical fiber has the core having a diameter of 20 to 130 μm and a clad provided around the core, and wherein the clad is made of resin and has a thickness of 10 to 40 μm,
• wherein the optical fiber is bent to be arranged between the first sheet and the second sheet, and
• wherein the wire intersects the optical fiber between the first sheet and the second sheet, and a flexural rigidity of the wire is equal to or greater than the flexural rigidity of the optical fiber.