Lateral Asymmetry in cladding of the Photonic crystal (PhC) waveguides has been utilized to demonstrate a compact TM-Pass polarization filter. The filter, which covers the entire conventional `C'- band of telecom spectrum has a low insertion loss and gives ≈ 41 dB extinction ratio at 1550nm wavelength.
In this paper, a slotted photonic crystal nanobeam cavity (SPCNC) based sensor has been proposed. The design consists of two rows of parabolically tapered holes and a discontinuous periodic slot in between the two rows of holes. The idea behind the discontinuous slot is to confine light tightly in the low refractive index medium of the structure and thereby increase the sensitivity of the sensor. The slot parameters and the radii of the tapered holes are optimized to achieve a very high Q-factor and sensitivity in the order of ~2.1×106 and 512 nm/refractive index unit respectively. Hence, the proposed structure can be considered as an ideal platform for lab-on-chip gas sensors.
An ultra-compact TE-Pass polarization filter has been designed using silicon-on-insulator based W1 Photonic crystal (PhC) slab waveguide structure. The proposed filter has been designed by judicial choice of dimensions of the W1 PhC waveguide, so that it can pass only the TE polarized light and block the TM polarized light. A high extinction ratio ≈34 dB, with nearly ≈1.5 dB insertion loss, has been achieved at wavelength 1550 nm in ≈5 μm long device. The simple structure of the device can be fabricated in single step of lithography with the well-established CMOS fabrication technique.