(a) Scanning-electron microscope image of a cleaved laser facet. (b) Measured two-dimensional beam profile showing a single mode. The inset shows the laser beam divergence in both the vertical and lateral directions.
Total average optical power (twice the single-facet output) from a laser with as-cleaved facets driven with current pulses and repetition rate (50% dc) at . The slope efficiency of is almost constant in the current range between 400 and . The inset shows the total average power of the laser driven with current pulses as a function of duty cycle. (100% duty cycle means that the laser was driven with a constant current source.)
(a) Total average emission power as a function of duty cycle for a laser with as-cleaved facets. The current pulse length is . The different curves correspond to various heat-sink temperatures controlled by using a double-stage thermoelectrical cooler. The inset shows a high-resolution, , Fourier-transform spectrum of the laser driven with long current pulses at temperature. (b) Optical emission power averaged during the pulse at drive current as a function of duty cycle at various temperatures. [Temperature assignment for different line styles is the same for parts (a) and (b)].
Data points correspond to the increase in the active region temperature due to duty cycle for quasi-cw operation. The dashed line is a linear fit of these data and imply that the thermal resistance is and the thermal conductance is .
Threshold current density of a laser with as-cleaved facets in pulse and cw operations. Data analysis after Ref. 28 gives a thermal resistance of corresponding to a thermal conductance per unit area of .
(a) Total average emission power as a function of duty cycle for a laser with as-cleaved facets. The current pulse length is . The different symbols correspond to various heat-sink temperatures controlled by using a He-flow cryostat. (b) Peak optical power averaged over the pulse length at drive current as a function of duty cycle at cryogenic temperatures. These data imply a thermal resistance of corresponding to .
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