DIRECTIONAL COUPLER FOR POLARIZATION PLANE MAINTAINING OPTICAL FIBER ABRADED IN LONG AXIS DIRECTION OF ELLIPTIC JACKET

摘要

PURPOSE:To improve polarization maintainability, i.e. a quenching ratio by embedding an elliptic jacket so that its long axis direction is perpendicular to the surfaces of the 1st and the 2nd quartz substrates. CONSTITUTION:A quartz substrate 23 is provided with a groove 22 which is as wide as or up to 30mum wider than the outer diameter of an elliptic jacket type polarization plane optical fiber (SPF21) so as to embed the SPF21. The SPF21 is embedded in the groove 22 together with resin 24 so that the long axis direction of the elliptic jacket 3 of the SPF21 is perpendicular to the surface of the quartz substrate 23 within an error range of <=+20 deg.; and the SPF21 is fixed in the quartz substrate 23 and the surface of the quartz substrate 23 is polished together with the SPF21 until light propagating in the core 1 of the SPF21 leaks out. Then, two quartz substrates 23 manufactured as mentioned above are used and coupled mutually one over another through a refractive index matching liquid 25 to obtain a polarization plane maintaining coupler.