We demonstrate a polarization-insensitive multiple-quantum-well optical amplifer for 1.3 μm wavelength in AlGaInAs-InP material system, using three tensile strained wells with strain of 0.36% in the active region. The amplifiers were fabricated forming ridge waveguide structure, which showed excellent polarization insensitivity (less than 0.6 dB) over the entire range of wavelength (1.28 μm ~ 1.34 μm) and a gain of 22.5 dB at the bias current of 200 mA and 1304 nm wavelength.
