Impact of signal filling factor for switching in reflective vertical cavity-based fast semiconductor saturable absorbers

ABSTRACT

A numerical model on reflective vertical cavity-based fast semiconductor (carrier recombination time in ps regime) saturable absorbers (VC-FSSA) is investigated for all-optical high-speed future applications, where the fluctuation of cavity optical length due to thermo-optic effects and cavity heating, and optically induced carrier density change are considered simultaneously with the increase of input signal intensity. The phase-shift due to thermal-optic effects and cavity heating is very important for high-speed device performances. At first, intensity and wavelength bi-stabilities are modelled with the different intensity time filling factor of RZ modulated pump signals and also, with the different input intensities, where the intensity tuning time is considered at few μs. Then the inverse saturation characteristics of reflectivity for the universal logic operations are shown for probe signal with the proper wavelength, which can control the negative effects of optically induced heating effects. These characteristics can be used for the high-speed thermally stable bi-stable optical switch and all-optical logic applications.

Keywords:

• Nonlinear Fabry–Perot cavity
• multiple quantum-well
• optical saturable absorption
• saturation nonlinearity in index change
• thermo-optic effects
• all-optical logic operations

Acknowledgment

The author would like to acknowledge Professor Prasanta Kumar Datta, IIT Kharagpur, India. The author also likes to acknowledge the Learned Reviewer for his valuable comments.