Vector structured beams (VSBs) offer infinite eigenstates and open up new possibilities for high-capacity optical and quantum communications by the multiplexing of the states. Therefore, the sorting and measuring of VSBs are extremely important. However, the efficient manipulations of a large number of VSBs have simultaneously remained challenging up to now, especially in integrated optical systems. Here, we propose a compact spin-multiplexed diffractive metasurface capable of continuously sorting and detecting arbitrary VSBs through spatial intensity separation. By introducing a diffractive optical neural network with cascaded metasurface systems, we demonstrate arbitrary VSBs sorters that can simultaneously identify Laguerre–Gaussian modes (l=−4 to 4, p=1 to 4), Hermitian–Gaussian modes (m=1 to 4, n=1 to 3), and Bessel–Gaussian modes (l=1 to 12). Such a sorter for arbitrary VSBs could revolutionize applications in integrated and high-dimensional optical communication systems.
In this paper, the silicon avalanche photodiode (Si-APD) size in micron, which was comprised of separate layer of
absorption charge and multiplication (SACM) has been studied. The influence of different thicknesses and different
doping concentration of the absorption, charge and multiplication layer on the electric field distribution, current-voltage
characteristic and breakdown voltage were simulated and analyzed respectively. The structural parameters optimization
has be done with the simulation results. The results show that the better gain and low bias voltage can be achieved with
layer thicknesses in micro/nano-sized, which can give a high gain of 106 and low bias voltage of 127V. Also the
fabrication process conditions has been given.
A new optical isolator mode which is based on the theory of SPP has been designed. A dielectric
waveguide and a SPP waveguide are formulated. And there is a gap in the middle of the core in the
dielectric waveguide. Low refractive index material is filled into the gap and the total reflection is
satisfied at the interface of the two materials. Magneto-optic material is contained in the two
waveguides and the two waveguides are stacked together. For the phase matching of the two
waveguides and the total reflection at the gap, the light couples from the dielectric waveguides into
the SPP waveguides. With the help of the SPP, the light passes the gap successfully and couples into
the dielectric waveguide again. However, there is a different situation at the reverse direction. For
the effect of the magnetic field, the permittivity of magneto-optic material has been changed and this
caused the phase mismatching of the two waveguides. So effective coupling is not able to finish
between the two waveguides. With the total reflection at the gap of the core, the light cannot traverse
the mode, and the aim that reflected light should be isolated is achieved. The insertion loss value is
1.72dB when the light traverses through the optical isolator in forward direction. In the reverse
direction, the isolation value is 34.14dB. And this result is better than the common magneto-optical
isolator.
GRIN medium with a lateral sech refractive index variation, can make normal-incident light beam gradually
curve to the medium with a larger refractive index, and periodically converge the light beam to a point smoothly
and continuously. This property of GRIN medium can be used as a coupl er to realize a mode spot size
conversion. This paper mainly discussed the transmission property of Gaussian light beam in a sech GRIN
medium by numerical simulation. SOI waveguide is widely used in the photonic integrated circuit. To achieve a
higher coupling efficiency between single mode optical fiber and single mode SOI slab waveguide, which suffer
a great light beam coupling loss for the mismatch of the spot size. The GRIN medium coupling structures are
designed as a coupler, with symmetric refractive index distribution and asymmetric refractive index distribution.
The insertion loss calculated in theory are 0.71dB and 1.35dB respectively, which has a significant improvement
in coupling loss, compared with the 30dB coupling loss caused by direct butt -joint transmission.
This paper discusses some advantages of IC thin film technology in realizing RC array that traditional thick film
technology does not have, which make IC thin film technology the mainstream in realizing RC array devices. Then it
focuses on how to use IC thin film technology to realize high precision RC array, some practical techniques are put
forward, based on our experiments and experience in layout design and fabrication. These techniques are demonstrated
separately according to the respective characteristics of resistor and capacitor. Finally, the different ranges of precision of
the devices tested in different ways through specific experiments are given.
In this paper, we have proposed a new type of DIRIM with suspended membrane resistor (SMR) structure, while mainly
focusing on its implementation technology which includes selection of resistance material and fabrication technique of
the membrane; design of Read-In-Integrated-Circuit; and implementation of silica-base MEMS process. Some
performance parameters of the device are quoted to conclude the advantages of this new type of DIRIM and make an
outlook on the key development in the future.
This paper presents a new image decomposition scheme that utilizes coding of convex hulls corresponding to a set of order statistic filters. The encoding of convex hulls can be done more efficiently than the encoding of the original image especially when the boundaries of the encoded set are rough.
A programmable hybrid binary image prossor based on morphological transformations is described and its applications are discussed. Using liquid crystal light modulators the fundamental operations of morphological transformations are realized optically.
A liquid-crystal optical modulator called the 2DPL-LCLM is designed to perform 2D pattern-logic operations that can be used in optical digital computations. The structure includes a layer with an array of patterned transparent electrodes between the dielectric mirror and the light-blocking layer. The utility of the device is demonstrated with an application to truth-table look-up symbolic substitution in digital optical computing that demonstrates resilience to the pattern-shift of the technique
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