| 摘要 |
PROBLEM TO BE SOLVED: To provide a inexpensive and compact two-way optical communication device and a two-way optical communication equipment with which the variation of the reception efficiency depending on a transmission distance is decreased, the limitation on the transmission distance is decreased, and a cross talk between transmitting and receiving lights is decreased. SOLUTION: The relation θfb <=0<=θfa or θfa <=0<=θfb is satisfied when inclination angles θfa and θfb of the outermost periphery based on the aperture number NA of a transmission light 8 after incidence with respect to the optical axis of an optical fiber 2 are given by θfa =Sin<-1> [ n0 Sin(θL+Sin<-1> (NA)/n0 +θT)}/ nf -θT, and θfb =Sin<-1> [ n0 Sin(θL-Sin<-1> (NA)/n0 +θT)}/nf -θT) where θL stands for an angle between the optical axis of the transmission light 8 and the optical axis of the optical fiber 2, θT stands for an angle between the normal line of the end face of the optical fiber 2 at the position S, NA stands for the aperture number before the transmission light 8 is made incident on the optical fiber 2, nf stands for the refractive index of the core of the optical fiber 2, and n0 stands for the refractive index of air. |
