Feature Issue on Optical Performance Monitoring (OPM). An integrated, high-resolution spectral polarimeter is demonstrated in 4%-index-contrast Ge-doped silica waveguides. A ring resonator achieves a wavelength selectivity of less than 2 GHz FWHM, and tunability is realized via thermo-optic phase shifters with scanning speeds on the millisecond time scale. Real-time, in-service polarization-mode dispersion monitoring is thus possible for studying dynamic channel behavior and for feedback to adaptive compensators. Measurements of the differential group delay, output state of polarization, and principal states of polarization of 10- and 40-Gbit/s modulated signals are presented. Measurements of time-varying PMD and higher-order PMD are also presented to demonstrate the device's capability.