Light propagation in strip and slot waveguide arrays for sensing are proposed and analyzed with a new theory of quantum walk. The waveguide arrays are designed on silicon-on-insulator and can be fabricated with mature and cost-efficient complementary metal-oxide semiconductor technology. A new slot waveguide array modified by conventional strip waveguide array with electric field mainly confined in the cladding region is investigated. Quantum walks have an exact mapping to classical phenomena as verified by experiments using bright laser light, so that they are introduced in our work as theoretical foundation. We take the width of waveguide of 450 nm and the coupling distance of 200 nm for strip waveguide array, and 420 nm and 180 nm for slot waveguide array, but with a 100nm slot in the center of waveguide. At last the waveguide array covered by a thin layer of graphene is investigated, which brings higher sensing property as well as a much better biocompatibility. With the monochrome light injection the intensity distribution at the end of the arrays changes with the refractive index of the sensing area (cladding region) and it can be explained by quantum walks theory. The designed waveguide arrays can possess compact footprint and high refractive index resolution, reaching 1E-11 RIU theoretically.
Search on improved-glued-binary-trees is a representative example of quantum superiority, where exponential acceleration can be achieved using quantum walk with respect to any classical algorithms. Here we analyzed the evolution process of this quantum-walk-based algorithm. Several remarkable features of the process are revealed. Generation of the model by introducing tunable defect strength and double defects is also discussed and the effects of these generalization on evolution process, arrival probability and residual probability are discussed in details. Physical implementation with silicon ridge waveguide array is presented. The design of the array with FEM method are presented and light propagation simulation with FDTD method shows that this kind of structure is feasible for the task. Lastly, preliminary experimental demonstration with classical coherent light simulation are presented. Our results show that silicon photonic chips are suitable for such search problems and opening a route towards large-scale photonic quantum computation.
We report the first demonstration of blue shift of optical pumping photonic crystal (PhC) laser. A femtosecond laser was
used to pump the InGaAsP based two dimensional photonic crystal laser at room temperature. Linear dependence of the
resonance wavelength with respect to the pump power is observed: dλ/dP=-1.5×10-2 nm/μW . Blue shift of overall
1.1nm was obtained with the increase power of pump laser. These results are in agreement with theoretical expectation
while the carrier-induced index change is introduced into the PhC semiconductor laser. It shows a possibility that by
proper wafer design and careful optimization, we may obtain wavelength stable photonic crystal laser, which is
important in photonic integration.
We design photonic crystal (PC) array surface emitting lasers with large-area coherence. The structure has six-fold rotational symmetry. By finite-difference time-domain method, we investigate the far-field characteristics of the individual element and the array. We demonstrate theoretically that the coherent PC array has lower far-field divergence angles and higher power compared to those of individual elements. Our PC array exhibits strong leaky coupling which has high mode stability and high intermodal discrimination. Thus, the coherent PC array shows great potential for high power low divergence in-phase surface laser emitting.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.