Tunable-gain lasing semiconductor optical amplifier

A gain-clamped semiconductor optical amplifier apparatus comprising:

• a semiconductor gain medium for amplifying an optical signal to generate an amplified optical signal;
• a first surface of the semiconductor gain medium for receiving the optical signal;
• a second surface of the semiconductor gain medium for outputting the amplified optical signal;
• an optical cavity including the semiconductor gain medium, a first mirror, and a second mirror opposing the first mirror;
• a photon mode associated with the optical cavity;
• a cavity loss associated with a loss of photons at the photon mode;
• a cavity gain associated with a gain of photons at the photon mode;
• a pumping mechanism coupled to the semiconductor gain medium;
• where the pumping mechanism is operated above a lasing threshold level so that the cavity gain is substantially in equilibrium with the cavity loss, and amplification of the optical signal by the semiconductor gain medium is substantially constant over a range of optical signal strengths;
• and
• where amplification of the optical signal by the apparatus is tunable.