1550 nm Polarization Insensitive Laterally Tapered Travelling-Wave Semiconductor Laser Amplifiers with a Narrow Circular Beam Divergence

A polarization-insensitive laterally tapered travelling-wave semiconductor laser amplifiers (TWSLAs) with a narrow circular beam divergence have been fabricated using metal-organic vapor phase epitaxy (MOVPE) technique. A narrow circular beam divergence of 20 degrees x20 degrees, an amplified spontaneous emission (ASE) ripple of 1.0 dB, and a polarization sensitivity of 1.5 dB were obtained at 27.8 dB chip gain.