Method for manufacturing a waveguide including a semi-conducting junction

A method for manufacturing a waveguide including a semiconducting junction, the method comprising:

• providing a support comprising a semiconducting layer having at least one first part of a first conductivity type comprising a concentration of first conductivity-type dopants,
• protecting the first part of the semiconducting layer by providing a protection of the first part,
• selectively implanting dopants of a second conductivity type opposite to the first conductivity type in a second part of the semiconducting layer, the implantation selectivity being achieved by means of the protection of the first part so that the second part is adjacent to the first part, the implantation being made so that the concentration of second conductivity-type dopants in the second part is greater than the concentration of the first conductivity-type dopants in the first part,
• diffusing the dopants of the second conductivity type in the first part to form a semiconducting junction in the first part,
• after the steps of implanting and diffusing have been performed, partially etching the semiconducting layer to form the waveguide in the first part, the protection of the first part being used during this etching to bound a first side wall of the waveguide at the interface between the first and the second parts so that the semiconducting junction is included in the waveguide.