Fabrication of biconically fused fiber polarization beamsplitters with various working wavelengths selected using a 1523-nm monitoring laser

The working-wavelength selectability of biconically fused fiber polarization beamsplitters made with extremely weakly fused couplers is presented. The point before or behind the first polarization modulation waist point in the power transfer curve monitored with unpolarized 1523-nm He-Ne laser light was taken as the stopping point in the coupler drawing process. The working-wavelength selection range as wide as 304 nm has been achieved, with the average polarization bandwidth being 34 nm.