We propose a compactly integrated transverse-magnetic (TM)-pass polarizer based on rectangular-shape onedimensional photonic-crystal silicon waveguide with an extremely high polarization extinction ratio of >30 dB and low insertion loss (~1 dB) over a broad wavelength range of 210 nm from 1,460 nm to 1,670 nm. The polarizer has been numerically simulated using three-dimensional finite-difference time-domain (3D FDTD) method. The optimum length of the proposed TM-pass polarizer is about 4 μm. At the 1,550 nm wavelength, the simulated polarization extinction ratio of the polarizer is 36 dB, and its corresponding insertion loss is about 1 dB.
This paper presents our recent achievement with a simple white-light Mach-Zehnder (MZ) interferometric method to
identify localized group velocity dispersion (GVD) coefficient or group delay dispersion (GDD) value of the
nanostructured silicon waveguide devices (NSWDs). Conventional methods of measuring the GVD of optical fibers or
waveguides are related to measurement of the total GVD of the entire fibers or NSWDs. Recently time-resolved
heterodyne detection technique and the near-field scanning microscopy technique are demonstrated to measure localized
group delay of the photonic crystal waveguides (PhCWs) devices, but the techniques have a limited group delay (GD)
resolution depending on laser pulse-width used for the measurement. It is demonstrated that our white-light
interferometric method can measure very accurate GDD value up to 0.5 fs/nm resolution. This method has been applied
to determine not only the GVD or GDD profile of the entire NSWDs but also that of their localized structural sections,
such as grating couplers and interface between the plain strip waveguide and single line-defect (W1) PhCW.
We report a white-light Mach-Zehnder interferometry method for an accurate measurement of spectral distribution of the
chromatic dispersion coefficient of very short optical waveguides over a wavelength range of 1520~1560 nm. The
chromatic dispersion curve of a 7.6 mm long silicon nano-waveguide of 400 nm width and 250 nm height was
successfully measured by confirming the method with standard single-mode fibers up to 3 cm length, for which its total
chromatic dispersion is as small as 0.51 fs/nm. This method will be very useful for determination of chromatic dispersion
profile of compact nanowaveguide devices.