| Photonic crystals are structures with dielectric constants modulated in one, two, or three dimensions. They are an interesting subject of active research due to their ability to control the flow of light on a very small-length scale. In the research for this thesis, two integrated photonic devices were designed, fabricated and characterized which utilize the special optical properties of photonic crystals.; The first device is a photonic crystal-photodiode micro-electro-optic filter, where a vertical self-assembly method was employed to grow a 3D face-centered cubic (FCC) photonic crystal over a working electro-optic device, a photodiode and a photodiode-plus-preamplifier made using conventional CMOS techniques. The objective of this project was to judge the practicality of the process and to observe the effect of the photonic crystal on the spectral response of the photodiode and photodiode-amplifier. Spectral measurements taken using a grating monochrometer confirmed that a stop band exists in the photocurrent response of this integrated photonic device, photonic crystal photodiode filter, at the predicted wavelength of 600 nm. These results were consistent with the simulation results made by using a 1D slab structure model. Although many groups have developed procedures to successfully grow self-assembled photonic crystals on substrates, we believe this is the first application of grown opals over functioning integrated electronics. This work explored the ability to include photonic functionality on the wafer with integrated electronic circuitry, and demonstrated a simple, practical and economic way to achieve it.; The second device is a tunable planar waveguide with an optically defined 1D photonic crystal cladding layer. In this section a planar waveguide with a photosensitive cladding layer (mixture of PMMA co DR1 and side-chain nematic liquid crystal polymer) that is optically addressable and reversible is presented. The maximum of intensity decrease of the infrared light (1440 nm) propagating through the waveguide reached 70% at a rotation angle corresponding to the Bragg condition (Λ = 1.5 mum), and rapidly decreased at adjacent angles. The full width at half maximum (FWHM) of the photo response of the device was 22 nm, and the grating could be erased by circularly polarized light. The device also worked successfully with a different Bragg grating periodicity (Λ = 1.2 mum). This grating in the cladding layer can be regarded as a 1D photonic crystal that interacts strongly with the light in the waveguide as a result of the slow light phenomenon. This waveguide provides a real-time optical control of the transmission spectrum at relatively low speed. The rise time is slow (1s) but may still be useful in many applications such as sensors, neural networks, or crossbar switches where extreme high speed is not necessary. |
