Large-angle 1.3-µm InP/InGaAsP digital optical switches with extinction ratios exceeding 20 dB

Photonic switching is of interest for network reconfiguration, high-speed LANs, and optical cross connects.1-3 The adiabatic- modal-evolution, asymmetric digital optical switch (DOS) is a promising candidate for these applications. It can operate independent of light polarization, it is less sensitive to wavelength and fabrication uncertainties than are conventional directional couplers, it switches completely for sufficient induced asymmetry, and because it is a semiconductor, it may be integrated with other active devices. But for the DOS to achieve this potential, two deficiencies must be overcome. Its size must be reduced by increasing the opening angle, and to allow for cascading of switches, high extinction ratios must be achieved.