Optical communications system and vertical cavity surface emitting laser therefor

An optical communications link, comprising:

• a single transverse mode, multiple longitudinal mode optical source;
• an optical receiver;
• and
• a single mode optical fiber for transmitting an optical signal generated by said optical source to said optical receiver;
• said optical receiver being sufficiently close to said optical source to effectively make attenuation and chromatic dispersion of the optical signal between said optical source and said optical receiver nonlimiting factors in designing the optical communications link.

An apparatus for facilitating data communications between a source location and a receiver location, comprising:

• a plurality of vertical cavity surface emitting lasers (VCSELs) at the source location, each VCSEL emitting an optical signal corresponding to a different source channel, each VCSEL being designed to operate in a single transverse mode, multiple longitudinal mode manner;
• a wavelength division multiplexing (WDM) device for combining said plurality of optical signals into a single wavelength division multiplexed (WDM) signal;
• and
• a single mode optical fiber for transmitting said WDM signal to said receiver location.

A single transverse mode, multiple longitudinal mode VCSEL configured to operate at a wavelength above 1200 nm, comprising:

• a first distributed Bragg reflector (DBR) and a second DBR defining a vertical cavity therebetween having an effective cavity length;
• a spacer layer lying within said vertical cavity, said spacer layer occupying more than fifty percent of the effective cavity length;
• and
• an active region lying in said vertical cavity, said active region having a gain spectrum lying above 1200 nm;
• wherein said spacer layer is sufficiently thick for said vertical cavity to accommodate at least two longitudinal modes within said gain spectrum.

A method for fabricating a vertical cavity surface emitting laser (VCSEL) having a concave reflective surface therein, comprising the steps of:

• forming a concave well in a substrate;
• forming a first reflective element conformal to said concave well;
• forming a spacer layer immediately above said first reflective element, said spacer layer being optically inactive with respect to an electric current therethrough;
• forming active region layers above said spacer layer, said active region being optically responsive to an electric current therethrough;
• and
• forming a second reflective element above said vertical cavity layers.

A method for fabricating a vertical cavity surface emitting laser (VCSEL) having a convex reflective surface therein, comprising the steps of:

• forming a substrate having a convex structure thereon;
• forming a first reflective element conformal to said convex structure;
• forming a spacer layer immediately above said first reflective element, said spacer layer being optically inactive with respect to an electric current therethrough;
• forming active region layers above said spacer layer, said active region being optically responsive to an electric current therethrough;
• and
• forming a second reflective element above said vertical cavity layers.

An apparatus, comprising:

• a plurality of optical communication links, each optical communications link comprising:
• a single transverse mode, multiple longitudinal mode optical source;
• an optical receiver;
• and
• a single mode optical fiber for transmitting an optical signal generated by said optical source to said optical receiver;
• wherein said single mode optical fibers are contained in a common multifiber cable extending from a first location containing said optical sources to a second location containing said optical receivers;
• and
• wherein said second location is sufficiently close to said first location to effectively make attenuation and chromatic dispersion of each of said optical signals nonlimiting factors in designing its respective optical communications link.

An apparatus, comprising:

• a plurality of WDM optical communication links, each WDM optical communications link comprising:
• a plurality of optical sources, each optical source generating a component optical signal;
• a multiplexer for combining the component optical signals into a WDM optical signal;
• an optical fiber for transporting said WDM optical signal;
• a demultiplexer for receiving said WDM optical signal and separating it back into its component optical signals;
• and
• a plurality of optical receivers for receiving said component optical signals;
• wherein said optical fibers are contained in a common multifiber cable extending from a first location containing said optical sources to a second location containing said optical receivers;
• and
• wherein said second location is sufficiently close to said first location to effectively make attenuation and chromatic dispersion of each of said WDM optical signals nonlimiting factors in designing its respective WDM optical communications link.