Abstract
This paper overviews the current status of polarization bistable VCSELs and their applications to alloptical
signal processing. We measured the bit error rate (BER) of flip-flop operations and obtained a
good BER value of 1.56 × 10‒10. We also measured the BER of flip-flop operations with AND gate
functionality. From the BER variation for the set pulse power, we found that fluctuations of the
switching threshold and the phase at the combination of the data and the set pulses affected BER. We
demonstrated all-optical 2-bit recognition and packet switching using two 1.55-μm polarization bistable
VCSELs. Optical packets including 40-Gb/s NRZ pseudo-random bit-sequence payloads were
successfully switched to the one of four designated ports, depending on the state of the two bits in the
headers with 4-bit 500-Mb/s RZ format. We also report a high-index-contrast subwavelength grating
VCSEL (HCG-VCSEL) that incorporates a polarization-independent HCG coupled with two orthogonal
in-plane output waveguides.
