Semiconductor optical amplifiers

Polarization insensitive semiconductor amplifiers are important devices for many applications. Their small size, high-gain, and ability to be turned on and off fast offer interesting possibilities for photonic switches. We have used a design to implement polarization insensitivity. Quantum wells of alternative compressive and tensile direction of strained are stacked up in the active region. Compressively strained layers provide TE gain through electron-heavy hole recombinations, while tensile strained wells provide predominantly TM gain through electron to light hole recombinations. Amplifiers can be fabricated at both 1.3 and 1.5 /spl mu/m wavelength.