Abstract: The present invention relates a fiber optical module. A first filter 5 transmits a light with a first predetermined wavelength (?A ), and reflects lights with a second predetermined wavelength (?B) and a third predetermined wavelength (?C). A second filter 6 transmits the light with wavelength ?B and reflects the light with wavelength ?C. A first light-receiving device 2 receives the light with wavelength ?A, and a second light-receiving device 3 receives the light with wavelength ?B, A light-emitting device 4 emits the light with wavelength ?C. A first optical fiber 1a leads the lights with wavelengths ?A and ?B to the first filter 5. A second optical fiber 1b leads the light with wavelength ?B reflected by the first filter 1a. A third optical fiber 1c leads the light with wavelength ?C emitted by the light-emitting device 4 to the second filter 6.

Abstract: A single core optical fiber cord having an outer diameter of 1.2 mm or less, and having a structure in which an optical fiber core wire having a resin coating provided at the center, a tensile-strength-fiber layer around the periphery of the optical fiber core wire, and a coating layer around the outer periphery of the tensile-strength-fiber layer is provided. The coating layer can be composed of a non-halogen fire-retardant resin. The optical fiber cord has excellent fire retardant, mechanical and handling properties, although the outer diameter thereof is 1.2 mm or less.