High Switching-Speed Operation of Optical Memory Based on Polarization Bistable Vertical-Cavity Surface-Emitting Laser

Operation conditions of all-optical buffer memories based on polarization bistable vertical-cavity surface-emitting lasers (VCSELs) were investigated. The switching power dependence on the frequency detuning of the input optical signal was measured for a 980-nm polarization bistable VCSEL. The proper operating conditions for 10-Gb/s memory operation were also measured and found to be on the negative detuning side. Calculations based on a two-mode rate-equation model successfully explained the measured characteristics of the switching power dependence on the frequency detuning and the operating conditions. Maximum data rates for the memory operation strongly depended on the Q factor (i.e., photon lifetime) of the VCSELs. A possibility of 40-Gb/s memory operation using a polarization bistable VCSEL with a Q factor as low as 500 was shown.