Directional coupler for optical communications system

A coupler for an optic data system, said coupler comprising:

• a first optical waveguide adapted for connection to a source and having a first core area,
• a second optical waveguide adapted for connection to an optical transmission network and having a second core area larger than said first core area,
• a detector port, and
• directing means in a path between said first and second optical waveguides for receiving an output optical beam from said second optical waveguide,
• said directing means having a face including both a passage-way portion for passing an input optical beam from said first optical waveguide to said second optical waveguide and a deflecting portion,
• said deflecting portion directing said output optical beam to said detector port with an efficiency substantially equal to the ratio of the area of said deflecting portion to the total area of said face.

A directional coupler for a time division multiplex optic data system, said directional coupler comprising:

• a first optical waveguide adapted for connection to a source,
• a second optical waveguide adapted for connection to an optical transmission network,
• a detector port, and
• beam coupling means between said first and second optical waveguides for receiving a first optical beam from said first waveguide and coupling said first beam to said second waveguide and for receiving a second optical beam from said second waveguide and coupling said second beam to said detector port,
• said coupling means including a beam-directing surface for receiving said second beam and directing said second beam to said detector port,
• said beam-directing surface defining an optical passageway for said first beam through said surface,
• said coupling means further including an optical transmission medium effective between said second waveguide and said beam-directing surface to expand said second beam,
• wherein said first optical waveguide has a first core area and said second optical waveguide has a second core area larger than said first core area.

A directional coupler for a time division multiplex optic data system, said directional coupler comprising:

• a first optical waveguide adapted for connection to a source,
• a second optical waveguide adapted for connection to an optical transmission network,
• a detector port, and
• beam coupling means between said first and second optical waveguides for receiving a first optical beam from said first waveguide and coupling said first beam to said second waveguide and for receiving a second optical beam from said second waveguide and coupling said second beam to said detector port,
• said coupling means including a beam-directing surface for receiving said second beam and directing said second beam to said detector port,
• said beam-directing surface defining an optical passageway for said first beam through said surface,
• said coupling means further including an optical transmission medium effective between said second waveguide and said beam-directing surface to expand said second beam,
• wherein said first waveguide includes an end portion aligned with said optical passageway and said end portion extends into said passageway, and
• wherein said end portion of said first optical waveguide defines a surface co-planar with said beam-directing surface.

A directional coupler for a time division multiplex optic data system, said directional coupler comprising:

• a first optical waveguide adapted for connection to a source,
• a second optical waveguide adapted for connection to an optical transmission network,
• a detector port, and
• beam coupling means between said first and second optical waveguides for receiving a first optical beam from said first waveguide and coupling said first beam to said second waveguide and for receiving a second optical beam from said second waveguide and coupling said second beam to said detector port,
• said coupling means including a beam-directing surface for receiving said second beam and directing said second beam to said detector port,
• said beam-directing surface defining an optical passageway for said first beam through said surface,
• said coupling means further including an optical transmission medium effective between said second waveguide and said beam-directing surface to expand said second beam,
• wherein said second waveguide has a first core area and said detector port has a second core area larger than said first core area.

A directional coupler for a time division multiplex optic data system, said directional coupler comprising:

• a first optical waveguide adapted for connection to a source,
• a second optical waveguide adapted for connection to an optical transmission network,
• a detector port, and
• beam coupling means between said first and second optical waveguides for receiving a first optical beam from said first waveguide and coupling said first beam to said second waveguide and for receiving a second optical beam from said second waveguide and coupling said second beam to said detector port,
• said coupling means including a beam-directing surface for receiving said second beam and directing said second beam to said detector port,
• said beam-directing surface defining an optical passageway for said first beam through said surface,
• said coupling means further including an optical transmission medium effective between said second waveguide and said beam-directing surface to expand said second beam,
• said directional coupler including a ferrule encompassing said first waveguide and further including a low-melting-point metal between said first waveguide and said ferrule for locating and retaining said first waveguide relative to said ferrule.

In a fiber optic data system including a transmission network and a data terminal having a source and a detector, a directional coupler for coupling a first non-collimated optical beam from said source to said transmission network and for coupling a second non-collimated beam from said transmission network to said detector;

• said directional coupler comprising:
• a detector port optically coupled to said detector,
• a first optical waveguide connected to said source and having a first core area,
• a second optical waveguide connected to said transmission network and having a second core area larger than said first core area, and
• directing means in a path between said first and second optical waveguides for receiving an output optical beam from said second optical waveguide,
• said directing means including a deflecting portion defining a passageway for passing an input optical beam from said first optical waveguide to said second optical waveguide,
• said directing means directing all of said output optical beam impinging against said deflecting portion to said detector port,
• said fiber optic data system including expanding means effective in a path between said second optical waveguide and said directing means for expanding said output optical beam.

A method for coupling optical beams in an optic data system including a detector, a first optical waveguide, a second optical waveguide, and an apertured beam-directing surface between said first and second waveguides;

• said method comprising the steps of:
• providing a first non-collimated optical beam having a first cross-sectional area at said first waveguide,
• transmitting said first beam from said first waveguide through the aperture in said beam-directing surface to said second waveguide,
• providing a second non-collimated optical beam having a second cross-sectional area larger than said first cross-sectional area at said second waveguide,
• transmitting said second beam from said second waveguide to said apertured beam-directing surface,
• expanding the cross-sectional area of said second beam between said second waveguide and said beam-directing surface,
• directing that portion of said second beam impinging upon said surface away from said aperture, and
• transmitting said portion of said second beam from said surface to said detector.