Two novel alternative methods for modulating semiconductor lasers that enable much higher frequency modulation.
Semiconductor lasers are usually modulated by changing the current to the laser, which changes the gain and causes the light output to change. The bandwidth of this is limited by the relaxation oscillation frequency and is typically 10 to 40 GHz.
Researchers at the University of California, Santa Barbara have developed two novel alternative methods for modulating semiconductor lasers that enable much higher frequency modulation. Rather than modulating the incoming current to the laser, the researchers propose modulating the loss in the cavity. This results in much faster modulation. Alternatively, in a ring laser significant impacts on modulation can be made by adding a second arm. By modulating the phase of light in this section, the light in the ring can add or subtract from the light in the separate arm. Further, it may be possible to modulate both the gain and the loss using either of these techniques to minimize pattern effects or minimize chirp in the laser.
This technology is available for licensing.
(PowerPoint Presentation) - Daoxin Dai, AW Fang and John E Bowers
|United States Of America||Issued Patent||8,693,509||04/08/2014||2009-428|
lasers, semiconductors, indoptoelectronics