Design and experimental demonstration of a semiconductor optical amplifier with enhanced spectral bandwidth and controllable spectral shape

A novel semiconductor optical amplifier (SOA) design is developed to address emerging opportunities in coarse wavelength division multiplexing and metro-area networks by providing enhanced spectral bandwidth with current-adjustable spectral shape. Multiple quantum-well SOAs are fabricated in the InGaAsP material system using molecular beam epitaxy at McMaster University. Each device is comprised of two electrically-independent sections along its length. An impurity-free quantum-well intermixing technique is used to introduce a relative shift between each section's gain spectrum. Optical gains up to 15 dB are observed from single- and two-section SOA devices 500 to 1600 μm in length. A 3-dB emission bandwidth of over 130 nm is measured from a two-section SOA through optimization of each section's injection current, demonstrating both bandwidth enhancement and electronic spectral tunability. This represents an improvement of 50 nm over the emission bandwidth of typical single section devices.