Patent ID: 6643424
Filing Date: 2003-11-04
Classification: G02B,G02F

Abstract:
A silicon oxynitride (SiON)/silicon dioxide (SiO2) optical waveguide switch comprising:a SiON/SiO2 optical waveguide structure; a UV wavelength tunable diffraction grating write source for generating a UV write beam for writing a diffraction grating pattern in the optical waveguide; a dither source producing a dither signal for modulating the wavelength of the UV tunable write source; a UV bandpass filter, receiving the UV write beam, and passing a center wavelength which will write the diffraction pattern in the optical waveguide; a dither-operated, wavelength-locked feedback loop, sampling the output of the UV bandpass filter and generating a feedback control signal for controlling the wavelength of the UV write source to write the diffraction grating pattern in the optical waveguide, or not a logic circuit for controlling the TV write source, wherein: to write the diffraction pattern, and if the feedback control signal indicates that the center wavelengths of the UV write source and the UV filter are aligned, then the logic circuit output is zero card no change is made to the center wavelength of the UV write source, and if the center wavelength of the UV write source and the UV filter are not aligned, the feedback control signal is used to determine in which direction and by what amount the drive signal of the UV write source is changed to bring them into alignment, and the feedback control signal is fed back to the UV write source to not write the diffraction pattern and if the feedback control signal indicates that the center wavelengths of the UV write source and the UV filter are not aligned, the logic output is zero and no change is made to the center wavelength of the UV write source, and if the feedback control signal indicates that the center wavelengths of the UV write source and the UV filter are aligned, then the feedback signal determines in which direction and by what amount the drive signal of the UV write source is changed to bring them out of alignment.