An economically manufacturable, continuous-wave single-mode quantum-dot laser with spectral width in excess of 20 nm and spectral wavelength between 1200 and 1320 nm has been developed at NL Nanosemiconductor (Dortmund, Germany). Special growth conditions for self-assembled indium arsenide-gallium arsenide quantum dots and a new laser-epitaxial-structure design were developed to enhance the effect of spectral-hole burning in diode lasers, achieving a reproducible shape of the lasing spectrum for a given value of the pump current.
Emerging applications for light sources with broad spectra include optical-coherence-tomography imaging systems, which typically use superluminescent LEDs or amplified-spontaneous-emission sources. Another high-volume potential for such devices may come with the introduction of silicon-based modulation technology, in which many parallel channels are pumped by one light source; having a laser that delivers light with high power density over a wide range of wavelength could prove beneficial for future wavelength-division-multiplexing silicon-photonic systems. The development of quantum-dot broadband lasers has been focused mainly on this kind of application, but work is also being done to extend the lasing spectrum to greater than 40 nm, targeting other opportunities such as medical and military applications. Contact Guido Vogel at [email protected].