Abstract: By judicious engineering of grating parameters such as tooth shape, duty cycle and phase offset, the grating strengths and effective indices of the polarization modes of a grated waveguide are adjusted over a wide range of values to achieve a desired level of polarization sensitivity, or insensitivity. In the typical example, the physical geometry of the grating teeth is adjusted so that degenerate behavior (nTE=nTM and ?TE=?TM) is obtained for two polarization modes; the effective refractive indices and grating strengths are matched for the TE and TM polarization modes. In the current embodiment the sidewall gratings are used in which the tooth profile is selected in order to equalize the grating strength for each polarization mode.

Abstract: A waveguide and resonator are formed on a lower cladding of a thermo optic device, each having a formation height that is substantially equal. Thereafter, the formation height of the waveguide is attenuated. In this manner, the aspect ratio as between the waveguide and resonator in an area where the waveguide and resonator front or face one another decreases (in comparison to the prior art) thereby restoring the synchronicity between the waveguide and the grating and allowing higher bandwidth configurations to be used. The waveguide attenuation is achieved by photomasking and etching the waveguide after the resonator and waveguide are formed. In one embodiment the photomasking and etching is performed after deposition of the upper cladding. In another, it is performed before the deposition. Thermo optic devices, thermo optic packages and fiber optic systems having these waveguides are also taught.

Abstract: By judicious engineering of grating parameters such as tooth shape, duty cycle and phase offset, the grating strengths and effective indices of the polarization modes of a grated waveguide are adjusted over a wide range of values to achieve a desired level of polarization sensitivity, or insensitivity. In the typical example, the physical geometry of the grating teeth is adjusted so that degenerate behavior (nTE=nTM and &kgr;TE=&kgr;TM) is obtained for two polarization modes; the effective refractive indices and grating strengths are matched for the TE and TM polarization modes. In the current embodiment the sidewall gratings are used in which the tooth profile is selected in order to equalize the grating strength for each polarization mode.