External cavity micro laser apparatus

External cavity micro laser apparatus, comprising:

• multimode micro laser means having an emission aperture and producing an output beam having a fundamental mode and multiple transverse lasing modes having a plurality of lasing lobe components;
• and optical waveguide means having a cladding and a core with an input aperture, said input aperture receiving said output laser beam from said laser means;
• imaging means laterally spaced from said input aperture receiving said output beam and imaging at said input aperture a far field spatial frequency distribution of said emission aperture in the slow axis plane, at which distribution said lasing lobe components are spatially distinguishable, said input aperture being sized and positioned to select one or more predetermined lasing lobe components;
• and partial reflecting means after said input aperture for returning a predetermined fraction of the optical energy in said waveguide means to said laser means, selected lasing lobe components mixing in said waveguide between said input aperture and said partial reflecting means such that the coherence of the output beam is thereby improved.

Micro laser apparatus, comprising:

• multimode micro laser means having an emission aperture and producing an output beam having a fundamental mode and multiple transverse lasing modes having a plurality of lasing lobe components;
• optical waveguide means having an input aperture;
• and imaging means for imaging at said input aperture a far field spatial frequency distribution of said emission aperture in a slow axis plane of the laser means, at which distribution said lasing lobe components are spatially distinguishable, said input aperture being sized and positioned to select one or more predetermined lasing lobe components;
• said optical waveguide means having a cladding and having a core with said input aperture, said input aperture receiving an output laser beam from said laser means and having laterally spaced therefrom mirror means for retuning back to said laser means laser energy which has been reflected from said laser means.

External cavity micro laser apparatus, comprising:

• multimode micro laser means producing output laser energy;
• an external cavity including said laser means and having first and second reflective means defining the boundaries of the cavity;
• optical waveguide means having an input aperture;
• imaging means for converging said output laser energy into said input aperture of said waveguide means;
• and partial reflecting means located beyond said input aperture and constituting said second reflective means for returning a predetermined fraction of the optical energy in said waveguide means to said laser means, wherein said partial reflecting means is wavelength selective and comprises a directional waveguide coupler coupled into said waveguide means followed in said waveguide means by wavelength-selective grating means which returns light in a selected band of frequencies back to said laser means.

External cavity micro laser apparatus, comprising:

• multimode micro laser means producing output laser energy;
• an external cavity including said laser means and having first and second reflective means defining the boundaries of the cavity;
• optical waveguide means having an input aperture;
• imaging means for converging said output laser energy into said input aperture of said waveguide means;
• and partial reflecting means located beyond said input aperture and constituting said second reflective means for returning a predetermined fraction of the optical energy in said waveguide means to said laser means, wherein said partial reflecting means comprises pulse-shaping means located in said laser-energy, said pulse-shaping means reflecting said predetermined fraction of laser energy from a back surface thereof.

External cavity micro laser apparatus, comprising:

• multimode micro laser means producing output laser energy;
• an external cavity including said laser means and having first and second reflective means defining the boundaries of the cavity;
• optical waveguide means having an input aperture;
• imaging means for converging said output laser energy into said input aperture of said waveguide means;
• and partial reflecting means located beyond said input aperture and constituting said second reflective means for returning a predetermined fraction of the optical energy in said waveguide means to said laser means, wherein said partial reflecting means is wavelength selective and comprises a fiber coupler on said waveguide means followed in said waveguide means by pulse-shaping means and mirror means which returns pulse-shaped laser energy to said laser means.

External cavity micro laser apparatus, comprising:

• multimode micro laser means producing output laser energy;
• an external cavity including said laser means and having first and second reflective means defining the boundaries of the cavity;
• optical waveguide means having an input aperture;
• imaging means for converging said output laser energy into said input aperture of said waveguide means;
• and partial reflecting means located beyond said input aperture and constituting said second reflective means for returning a predetermined fraction of the optical energy in said waveguide means to said laser means, and mode scrambling means located in advance of said input aperture for mixing the spatial modes of the waveguide means.