Semiconductor laser sources for optical communications

Summary form only given. High power sources are needed for optical communication links using direct and coherent detection techniques. The first experimental link to be tested is expected to use 0.85 μm wavelength lasers. The author has investigated multi-quantum well technology for single spatial mode lasers. The metal clad ridge waveguide uses a double-quantum well separate confinement structure fabricated by metal-organic chemical vapour deposition. Output power in excess of 312 mW CW has been achieved with output power in excess of 175 mW CW confined in a single spatial mode. Coherent detection requires a single mode, single frequency source with narrow linewidth, emitting greater output power than presently available. The state-of-the-art of coherent sources such as distributed feedback lasers, distributed Bragg reflector lasers and multi-quantum well techniques is reviewed. Technologies with potential for high-power narrow-linewidth operation are outlined