Semiconductor optical amplifier using energy from single-transverse-mode VCSELs to amplify optical signal

A vertically lasing semiconductor optical amplifier (SOA) for amplifying an optical signal, comprising:

• an integrated plurality of vertical cavity surface emitting lasers (VCSELs) having a common gain medium layer, and a signal waveguide extending horizontally through the VCSELs near the gain medium layer such that the optical signal is amplified while propagating therethrough;
• said VCSELs being functionally essentially isolated from each other, each building up its own lasing field, and each contributing only a small portion of an overall signal gain of said SOA;
• wherein effects of a local defect in the operation of a given one of said VCSELs are limited to the small contribution of that VCSEL to the overall amplification of the optical signal by said SOA, with overall SOA performance being reduced by only a minor amount;
• thereby achieving substantially smooth, single transverse mode lasing action of said VCSELLs for promoting spatially uniform and temporally stable gain of the optical signal as it propagates along the signal waveguide.

A method of amplifying an optical, comprising:

• providing a vertically lasing semiconductor optical amplifier (SOA) comprised of an integrated plurality of vertical cavity surface emitting lasers (VCSELs) having a common gain medium layer, and a signal waveguide extending horizontally through the VCSELs near the gain medium layer;
• providing substantial electrical isolation between said VCSELs to cause each to build up its own lasing field during operation of said SOA contributing only a small portion of an overall signal gain of said SOA;
• supplying an optical signal to an input of the SOA for amplification when propagating therethrough;
• and
• selecting operating parameters of said VCSELs to ensure that the contribution to each of the amplification of the optical signal by said SOA is small and effects of a local defect in the operation of a given one of said VCSELs are limited to the small contribution of that VCSEL to the overall amplification of the optical signal by said SOA, with overall SOA performance being reduced by only a minor amount;
• thereby achieving substantially smooth, single transverse mode lasing action of said VCSELLs for promoting spatially uniform and temporally stable gain of the optical signal as it propagates along the signal waveguide.