Large optical bandwidth and polarization insensitive semiconductor optical amplifiers using strained InGaAsP quantum wells

The material gain of equal width InGaAsP/InGaAsP multi-quantum well active layers is calculated solving the Luttinger-Kohn Hamiltonian, including tetragonal strain and confinement effects. The calculated optical bandwidth reaches 150 nm with a maximum polarization sensitivity of 1 dB between transverse electric (TE) and transverse magnetic (TM) emission over the -3 dB optical bandwidth. The corresponding device characterized by amplified spontaneous emission measurements shows an optical bandwidth with constant TE/TM ratio of almost 100 nm which can be improved up to 113 nm by increasing the barrier material band gap energy. Further enlargement of the optical bandwidth is expected by reducing the quantum well width. c 2010 American Institute of Physics. [doi:10.1063/1.3484151]