1.55 µm Polarisation Independent Semiconductor Optical Amplifier with 25 dB Fiber to Fiber Gain

Using a tapered in width square active waveguide and bulk InGaAsP/InP material we demonstrate a polarisation independent amplifier structure operating at 1550 nm with a reduced far-field divergence. Improvement of coupling efficiency enables us to achieve a 25 dB fiber to fiber gain together with 9 dBm fiber saturation output power for 150 mA bias current. A 200 ps gain recovery time allows fast gating or wavelength conversion.