JPS54151048A - Photo branching circuit - Google Patents

Abstract

PURPOSE:To achieve the improvement in the manufacturing efficiency of the photo branching circuit by butting optical fiber ends to themselves in the absence of adjustment within the trapezoidal grooves formed through chemical etching on a substrate thereby constituting the photo branching circuit. CONSTITUTION:A silicon wafer 1 is formed thereon with a trapezoidal goove 2 in which two optical fibers may be closely adjacently disposed and a trapezoidal groove 3 in which one optical fiber may be disposed, continuously through controlling of the plane bearing dependency of the rate of chemical etching and the quantity of the etching. This method enables the precision trapezoidal grooves of micron order to be readily obtained by the current etching techniques for controlling etching pattern accuracy and etching quantity. Hence, the optical fiber ends may be butted to themselves in the absence of adjustment within the trapezoidal grooves. It is also possible to change the butt ratios of the end faces 22, 23, 24 of the optical fibers and obtain desired photo distributing ratios by changing the etching pattern.