Shinsuke Takeuchi

Wavelength tuning in a grating-assisted vertical coupler filter using quantum well electrorefraction

We present a demonstration of the electro‐optic tuning in a GaAs/AlGaAs quantum well vertical codirectional coupler filter. Tunable range over 2 nm was realized through the quantum‐confined Stark effect with a tuning rate of 0.28 nm/V2 for transverse magnetic polarization. A filter bandwidth as narrow as 1.7 nm (full width at half‐maximum) at 830 nm with a coupling region length of 490 μm was obtained.

Grating-assisted directional coupler filters using AlGaAs/GaAs MQW waveguides

Wavelength demultiplexing in the 800 nm region is demonstrated using grating-assisted vertical codirectional coupler filters formed in two AlGaAs/GaAs multiple quantum well (MQW) ridge waveguides. A filter bandwidth as narrow as 3 nm (full width at half maximum) and interwaveguide coupling efficiency of 95% with a coupling length of only 430 mu m were achieved. Channel spacing of 4 nm was obtained for five-channel wavelength demultiplexing with crosstalk suppression in excess of 10 dB.<<ETX>>