Enhanced performance of InAs/GaAs quantum dot superluminescent diodes by direct Si-doping

Abstract

It is necessary to improve the output power and spectral width of superluminescent diodes (SLDs) simultaneously. In this paper, we show that both the output power and the spectral width of the SLDs based on InAs/GaAs quantum dots (QDs) can be significantly enhanced by direct Si-doping in the QDs. The maximum output power of the Si-doped QD-SLD reaches 20.5 mW at an injection current of 570 mA, while that of the undoped one with an identical structure is only 17.8 mW at the injection current of 550 mA. Moreover, the broadest spectral width of the doped QD-SLD is 105 nm, while that of the undoped QD-SLD is 93 nm. The enhanced performance of the doped QD-SLDs can be attributed to the direct Si doping that leads to inactivating the nonradiative recombination centers within or near the QDs and provides excess carriers to occupy the higher excited states.

Broadband chirped InAs quantum-dot superluminescent diodes with a small spectral dip of 0.2 dB

“…When the FWHM of the spectrum is at its broadest, the spectrum dip over this range is < 0.2 dB, which is smaller than that of the uniform multilayer QD-SLD. [18] Figure 3(c) shows the corresponding change in the FWHM of undoped and doped CMQD-SLD as the injection current increases. The spectral FWHM of the undoped sample continues to increase with increasing injection current.…”

“…[17] Recently, we reported that the spectrum dip is 1.2 dB for InAs/GaAs QD-SLD with direct Si doping in QDs when the spectral width was 105 nm. [18] For QD-SLDs with a central wavelength in the O-band, and utilizing the common contribution of GS and ES to broaden the spectrum, their spectrum dip is not less than 0.2 dB. [19][20][21] In addition, it is found that doping technology is often used to improve the performance of QD-SLDs, such as p-type modulation doping technology.…”

“…[24,25] Especially, it has been demonstrated that Si doping technology can simultaneously improve the output power and spectral width of QD-SLDs. [18] In this paper, we demonstrated enhanced performances of InAs/GaAs chirped multilayer quantum-dot superluminescent diodes (CMQD-SLDs) with direct Si doping compared with ones without any doping in QDs. It was found that the output power of the doped CMQD-SLD is always higher than that of the undoped CMQD-SLD at identical injection currents.…”

“…Moreover, the spectral dip of the doped CMQD-SLD is decreased to 0.2 dB, which is the same as the minimum reported for QD-SLDs with a central wavelength in the O-band. [17][18][19][20][21] The improved performance of doped CMQD-SLD can be attributed to the direct doping of Si in the QDs, which passivates the nonradiative recombination centers within or near the QDs and provides excess carriers to occupy the higher excited states. [18,[23][24][25] A shorter cavity length CMQD-SLD was also fabricated, and a maximum spectral width of 106 nm was obtained.…”

“…[17][18][19][20][21] The improved performance of doped CMQD-SLD can be attributed to the direct doping of Si in the QDs, which passivates the nonradiative recombination centers within or near the QDs and provides excess carriers to occupy the higher excited states. [18,[23][24][25] A shorter cavity length CMQD-SLD was also fabricated, and a maximum spectral width of 106 nm was obtained. In addition, through anti-reflection coating and device packing, the maximum output power and spectral width of CMQD-SLD with direct Si doping were increased to 16.6 mW and 114 nm, respectively.…”