Search

2-Bromobenzaldehyde reacts diastereoselectively with chiral alkanolamines under carbon monoxide in the presence of a catalytic amount of bis(triphenylphosphine)palladium(II) chloride to afford the corresponding tricyclic isoindolinones in moderate to good yields.

We report on the fabrication and characterization of broadband Bragg filters in microfabricated AlGaAs waveguides. Electron‐beam lithography and chemically assisted ion‐beam etching were used to fabricate first‐order gratings with 250 nm period. Bragg filters with rejection bandwidth ∼15 nm and centered at ∼1.6 μm are demonstrated.

We report all-optical switching with low-peak power in a microfabricated AlGaAs waveguide operating at 1.6 /spl mu/m. We show that by using a 1-/spl mu/m long microfabricated strongly-guided waveguide with 0.8 /spl mu/m by 0.9 /spl mu/m mode cross-sectional area, switching is achieved with an average power of 1.2 mW for 82-MHz mode-locked 430 fs pulses. The estimated peak pump power and pulse energy inside the microfabricated waveguide were /spl sim/30 W and /spl sim/14.6 pJ, respectively, which is 5-10 times lower than the values needed with conventional waveguides. In terms of a practicality index defined via switching power times waveguide length, this waveguide has around the best value. >

We report experimental results from an erbium‐doped gallium phosphide microdisk resonator pumped by a Ti‐sapphire laser at 980 nm. Fabrication and characterization of the microdisk resonator are discussed. Enhanced Er+3 intra‐4f‐shell photoluminescence was observed in the microdisk resonator due to microcavity effect and compared to a thin film sample. At low pumping power intensity, the photoluminescence from erbium‐doped gallium phosphide microdisks is an order stronger than that from a thin film sample.

We report our experiment on the use of a double‐disk structure to couple light output from a microdisk laser which allows us to maintain a high Q value of the microdisk resonator. The small photon leakage rate from the lower lasing disk to the top waveguiding disk can be carefully controlled by choosing the distance between the two disks. Various structures can be fabricated on the top disk to couple the light out. In this letter, a simple opening in the top disk is used for output coupling.