Negative electrical feedback grinrod external coupled cavity semiconductor laser

Presents a new configuration of a negative frequency feedback semiconductor laser. Instead of a Fabry-Perot etalon, an optical fiber ring resonator is used as the FM noise detector. All the components are connected by optical fibers. The spectral linewidth of the 1.3- mu m graded-index-rod external coupled cavity (GRECC) InGaAsP BH laser diode is narrowed by using the negative electrical feedback technique. The linewidth-power product and the minimum spectral linewidth are 3.4 MHz-mW and 850 kHz, respectively.<>