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1

Polarization-selective beam splitter by a sandwiched grating

Wang B, Chen L, Lei L, Zhou J

Optica Applicata

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2013

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Vol. 43, nr 2

s. 229-236

EN

We describe a polarization-selective beam splitter by a sandwiched grating, which can fulfill the high efficiency element for TE polarization and the two-port output for TM polarization. The modal method and the rigorous coupled-wave analysis (RCWA) are employed together to optimize the polarization-selective beam splitter. According to the modal method, the grating duty cycle and period are discussed to analyze the physical mechanism of such a dual-function element. Using RCWA, grating depth and thickness of the covering layer are accurately optimized to design such a polarization-selective beam splitter. With the optimized grating duty cycle, period, depth and covering layer thickness, TE polarization can be mainly diffracted in the –1st order and two-port output can be achieved for TM polarization in the 0th and the –1st orders. The polarization-selective beam splitter should be a useful element in a variety of applications with advantages of high efficiency, wideband property, and dual functions based on a sandwich grating.

2

Design technique for all-dielectric non-polarizing beam splitter plate

Rizea A.

Opto-Electronics Review

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2012

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Vol. 20, No. 1

96-99

EN

There are many situations when, for the proper working, an opto-electronic device requiring optical components does not change the polarization state of light after a reflection, splitting or filtering. In this paper, a design for a non-polarizing beam splitter plate is proposed. Based on certain optical properties of homogeneous dielectric materials we will establish a reliable thin film package formula, excellent for the start of optimization to obtain a 20-nm bandwidth non-polarizing beam splitter.

3

Reflective diffraction with high efficiency and beam splitter by metal-mirror-based grating

Wang B., Lei L., Chen L., Zhou J.

Optica Applicata

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2012

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Vol. 42, nr 3

473-479

EN

It is interesting and desirable to achieve two functions of high efficiency and two-port output with one reflective grating, which is not easy to acquire by multilayer coatings. We describe the reflective high efficiency element and the two-port beam splitter by the metal-mirror-based grating. By modal method, the design guideline is proposed according to the two-beam interference of the excited modes by incident TE and TM polarizations. Using rigorous coupled-wave analysis (RCWA), accurate grating parameters are optimized by numerical calculation. This indicates that wideband property can be achieved for such a reflective dual-function grating. Furthermore, the element can also be used for beam splitting for TE polarization with the pre-determined angle of incidence. With merits of wideband and so many functions, the reflective elements presented should be useful in a variety of optical systems.

4

Polarization-independent two-port beam splitter grating under second Bragg incidence angle with usual duty cycle

Wang B.

Optica Applicata

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2012

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Vol. 42, nr 1

69-74

EN

Based on the total internal reflection (TIR) under second Bragg incidence angle, polarization-independent two-port beam splitter grating etched in fused silica is described for the usual duty cycle of 0.5. There are three diffraction orders in the reflection: -2nd order, -1st order, and 0th order. The grating depth and period are optimized using the rigorous coupled-wave analysis (RCWA) in order to separate the incident wave into the -2nd and 0th orders with good uniformity and high efficiency for the TE and TM polarization wavelength of 800 nm. The diffraction properties for operation have been investigated for the incident wavelength and angle, indicating that good tolerance of incidence angle can be obtained for the designed beam splitter grating. Most importantly, the advantages of usual duty cycle of 0.5 and much shallower-etched depth will facilitate effective fabrication the reported beam splitter, which is of great significance for the practical use in numerous optical systems.

5

One-to-three and T-shaped beam splitters based on self-collimating photonic crystals

Wu Z, Xie K, Yang H, He X

Optica Applicata

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2012

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Vol. 42, nr 4

845--852

EN

In this paper, a one-to-three beam splitter and a T-shaped one-to-two beam splitter are proposed by introducing a V-shaped air gap into a self-collimating photonic crystal (PC). By adjusting the width of the introduced air gap to proper values, the incident beam can be divided into two or three sub-beams. The plane wave expansion method is employed to obtain the equifrequency contours and the band diagram of the PC. The splitting ratios between the sub-beams as a function of the width of the air gap are calculated by using the finite-difference time-domain method. Meanwhile, the field distributions of the light propagation in the structure are presented.

6

Simulation and design of a wideband T-shaped photonic crystal splitter

Foghani S., Kaatuzian H., Danaie M.

Optica Applicata

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2010

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Vol. 40, nr 4

863--872

EN

In this paper, a high efficiency 2-D T-shaped photonic crystal beam splitter is proposed. It consists of a square lattice of GaAs rods (n = 3.4) embedded in air. The photonic crystal structure proposed can be used for 1550 nm wavelength, which is an important wavelength for optical fiber data transmission. Finite difference time domain (FDTD) simulation results demonstrate that a conventional T-junction can only provide 78% transmission coefficient (39% for each branch) for the incident light, while the proposed T-shaped splitter transmits over 90% of the incident light beam (over 45% from each branch) in the single mode region of waveguide. Especially it transmits nearly 98% (49% from each branch) of the input light in the wavelength of 1550 nm. In other words, the proposed devise shows higher beam splitting efficiency and a wider range of flatness of transmission power spectrum in comparison with previous works.