Abstract: A semiconductor optical amplifier (SOA) apparatus and related methods are described. The SOA comprises a signal waveguide for guiding an optical signal along a signal path, and further comprises one or more laser cavities having a gain medium lying outside the signal waveguide, the gain medium being sufficiently close to the signal waveguide such that, when the gain medium is pumped with an excitation current, the optical signal traveling down the signal waveguide is amplified by an evanescent coupling effect with the laser cavity. When the gain medium is sufficiently pumped to cause lasing action in the laser cavity, gain-clamped amplification of the optical signal is achieved.

Abstract: A semiconductor optical amplifier (SOA) apparatus and related methods are described. The SOA comprises a signal waveguide for guiding an optical signal along a signal path, and further comprises one or more laser cavities having a gain medium lying outside the signal waveguide, the gain medium being sufficiently close to the signal waveguide such that, when the gain medium is pumped with an excitation current, the optical signal traveling down the signal waveguide is amplified by an evanescent coupling effect with the laser cavity. When the gain medium is sufficiently pumped to cause lasing action in the laser cavity, gain-clamped amplification of the optical signal is achieved.

Abstract: A ballast-powered semiconductor optical amplifier (SOA) apparatus and related methods are described. The SOA comprises a signal waveguide for guiding an optical signal along a signal path, and further comprises one or more ballast lasers positioned with respect to the signal waveguide such that the optical signal is amplified using energy from the lasing fields of the one or more ballast lasers. The problem of relative intensity noise (RIN) transfer from the ballast lasers into the optical signal is avoided by ensuring that the relaxation oscillation frequency (ROF) of each ballast laser is sufficiently higher than the signal modulation rate such that the RIN spectrum is tolerably low at the signal modulation rate. The ROFs themselves are manipulated by methods including adjustment of excitation current densities within the ballast lasers.

Abstract: A ballast-powered semiconductor optical amplifier (SOA) apparatus and related methods are described. The SOA comprises a signal waveguide for guiding an optical signal along a signal path, and further comprises one or more ballast lasers positioned with respect to the signal waveguide such that the optical signal is amplified using energy from the lasing fields of the one or more ballast lasers. The problem of relative intensity noise (RIN) transfer from the ballast lasers into the optical signal is avoided by ensuring that the relaxation oscillation frequency (ROF) of each ballast laser is sufficiently higher than the signal modulation rate such that the RIN spectrum is tolerably low at the signal modulation rate. The ROFs themselves are manipulated by methods including adjustment of excitation current densities within the ballast lasers.

Abstract: A semiconductor optical amplifier (SOA) apparatus and related methods are described. The SOA comprises a signal waveguide for guiding an optical signal along a signal path, and further comprises one or more laser cavities having a gain medium lying outside the signal waveguide, the gain medium being sufficiently close to the signal waveguide such that, when the gain medium is pumped with an excitation current, the optical signal traveling down the signal waveguide is amplified by an evanescent coupling effect with the laser cavity. When the gain medium is sufficiently pumped to cause lasing action in the laser cavity, gain-clamped amplification of the optical signal is achieved.