DFB laser incorporating novel curved-grating

Summary form only given. High power single-mode single-frequency laser sources are the key devices in various applications ranging from medicine to telecommunication (pumping of Er-doped fibre amplifiers for fibre optical communication). Unfortunately catastrophic optical damage and thermal overheating of the facet are limiting the output power of the single-element diode lasers based on a narrow stripe to less than 500 mW. Although higher powers may be achieved by increasing the stripe width, multiple lateral modes generally appear. Other approaches aimed at improving the diffraction-limited output power include arrays of antiguided narrow-stripe lasers, unstable resonators and master oscillator/power amplifier (MOPA) structures. Of these, only MOPAs have demonstrated diffraction-limited operation to output powers of >1 W, but the technology required to fabricate MOPAs is quite complex. We present a novel type of distributed feedback laser with a "curved-grooves" diffraction grating which is expected to give the enhanced spectral and spatial output beam characteristics.