Optical buffer memory based on polarization bistability in VCSELs

A novel optical buffer memory with a shift register function is proposed. The buffer memory consists of a two-dimensional array of polarization bistable VCSELs, in which the bit state of the optical signal, “0” or “1” is stored as a lasing linear polarization state of 0 or 90°. Input data stored as the polarization states of the first VCSEL are transferred to the polarization states of the second VCSEL. In our experiment using 980 nm VCSELs, 10 Gbit/s optical buffering has been successfully demonstrated. We have also demonstrated polarization bistability and all-optical flip-flop operation in 1.55 μm VCSELs.