Dual-core Photonic Crystal Fiber Polarization Research Articles

Dual-Core Photonic Crystal Fiber Polarization Beam Splitter Based on a Nematic Liquid Crystal with an Ultra-Short Length and Ultra-Wide Bandwidth

This paper presents a novel pentagonal structure dual-core photonic crystal fiber polarizing beam splitter (PS-DC-PCF PBS) filled with a nematic liquid crystal (NLC) in the central hole. Unlike previous designs with symmetric arrangements, the upper and lower halves of the structure have different air hole arrangements. The upper half consists of air holes arranged in a regular quadrilateral pattern, while the lower half features a regular hexagonal arrangement of air holes. By filling the central hole with birefringent liquid crystal, the birefringence of the structure is enhanced, reducing the coupling lengths along the x polarization and y polarization directions. The polarization properties, coupling characteristics, and the influence of different structural parameters on the extinction ratio of the polarizing beam splitter are analyzed using the full-vector finite element method. Simulation results demonstrate that the designed PS-DC-PCF PBS achieves a maximum extinction ratio (ER) of 72.94 dB with a splitting length of only 61.9 μm and a wide operating bandwidth of 423 nm (1.324–1.747 μm), covering most of the O, E, S, C, L, and U communication bands. It exhibits not only ultra-short splitting lengths and ultra-wide splitting bandwidth but also good manufacturing tolerances and anti-interference capabilities. The designed PS-DC-PCF PBS could provide crucial device support for future all-optical communication systems and has potential applications in fiber optic communication or fiber laser systems.

Ultra-broadband small-size dual-core photonic crystal fiber polarization splitter based on silver coating

We have proposed a novel silver-coated ultra-broadband small-size dual-core photonic crystal fiber (DC-PCF) polarization splitter which achieves a short length, high extinction ratio (ER) and ultra-wide bandwidth at the commonly used communication wavelength band. Finite element method-based numerical simulation is applied to carry out a thorough investigation for wavelength from 1 to 2 μm. According to the simulation results, the coupling qualities of the proposed structure can be improved by resonant coupling between the core guide mode and the surface plasmon polarization (SPP) exciton mode. By analyzing the change of ER with varying wavelength, the ER value of this work are achieved as 67.4 and 67.1 dB when the wavelength are 1.14 and 1.57 μm, respectively. The final splitting length (LS) is 17.17 μm. To the best of our knowledge, it is difficult to achieve in all previous studies. With a splitting bandwidth of 900 nm (1.0–1.9 μm) and the ER value of −50.1 dB at 1.55 μm, the E + S + C + L + U communication bands are completely covered. The proposed model has excellent beam-splitting performance, such as ultra-short LS, ultra-wide splitting bandwidth and good tolerance performance, with potential applications in optical fiber communications or fiber laser devices.

Design of an octagon structure dual-core photonic crystal fiber polarization beam splitter with a liquid crystal filled central hole

In this paper, an octagon structure dual-core photonic crystal fiber (OS-DC-PCF) polarization beam splitter (PBS) with a liquid crystal filled central hole is designed. The octagon lattice structure is simple and easy to fabricate. By filling the nematic liquid crystal into the central hole, the birefringence of the octagon structure can be enhanced, and the coupling lengths along the two polarization directions can be reduced. The full vector-finite element method is used to analyze the polarization and coupling characteristics, and the influences of different structural parameters on the extinction ratio (ER) of the PBS. The simulation results show that for the designed OS-DC-PCF PBS, the maximum ER is ∼91 dB, the splitting length is only 125μm, and the working bandwidth is up to 339 nm (1.493–1.832μm), covering the whole C+L+U communication bands. Moreover, it has good fabrication tolerances and anti-interference ability. It is believed that the designed OS-DC-PCF PBS can provide the critical device support for the future all-optical communication systems.

Design of a compressed hexagonal dual-core photonic crystal fiber polarization beam splitter with a liquid crystal filled air hole

A compressed hexagonal dual-core photonic crystal fiber (CH-DC-PCF) polarization beam splitter (PBS) with a liquid crystal filled air hole is designed. The designed CH-DC-PCF has different sizes of air holes, which are arranged in a compressed hexagonal structure in the cladding region and introduce the birefringence. In addition, the nematic liquid crystal is filled into the central air hole to enhance the beam splitting effect. To obtain a shorter PBS, the structure parameters of the CH-DC-PCF are optimized by the finite element method. The simulation results show that the length of the proposed CH-DC-PCF PBS is 109.5 μm, and the corresponding extinction ratio (ER) reaches the first peak value of 86.07 dB at wavelength 1.494 μm, then 63.14 dB at wavelength 1.55 μm, and the second peak value of 83.35 dB at wavelength 1.553 μm. Moreover, the ER is higher than 20 dB in the wavelength range of 1.402 to 1.682 μm, so the bandwidth of the PBS is up to ∼280 nm, covering the S + C + L + U communication band.

Ge20Sb15Se65 glass-based ultra-bandwidth X-shaped dual-core photonic crystal fiber polarization beam splitter with an air hole filled gold rod

In this paper, a novel X-shaped dual-core photonic crystal fiber polarization beam splitter (X-DC-PCF PBS) with an air hole filled gold rod based on G e 20 S b 15 S e 65 glass is proposed. According to the DC mode coupling theory and surface plasmon resonance effect, the mode coupling phenomena of the x polarization (X-pol) and y polarization (Y-pol) odd and even modes are analyzed, respectively. The variation laws of coupling lengths of the X-pol and Y-pol and the coupling length ratio with different structural parameters at wavelength 1.55 µm are investigated. When the shortest polarization splitting length ( L P S ) is 230 µm, there is only the X-pol and Y-pol light in the cores A and B, respectively. By considering the variation of the extinction ratio and insertion loss (IL) with wavelength, the final polarization splitting bandwidth (PSB) is 358 nm (1.367–1.725 µm), and the maximum ILs of the X-pol and Y-pol in the whole PSB are 0.04 and 0.8 dB, respectively. The proposed X-DC-PCF PBS has ultra-wide PSB, short L P S , and ultra-low IL, so it will play an important role in the development of optical integration technology and the construction of an all-fiber loop platform.

Ultra-Short Dual-Core Photonic Crystal Fiber Polarization Beam Splitter with Round Lattice and As2S3-Filled Center Air Hole

A circular ultra-short As2S3 filled double-core photonic crystal fiber polarization beam splitter is proposed. The finite element method is used to study the performance of the designed photonic crystal fiber polarization beam splitter. By filling high refractive index As2S3 into the central air hole, the coupling performance of the double-core PCF is improved. By optimizing geometric parameters, the splitting length of the circular beam splitter can be as short as 72.43 μm, and the extinction ratio can reach −151.42 dB. The high extinction ratio makes the circular polarization beam splitter have a good beam splitting function. The designed circular double-core photonic crystal fiber has the same cladding pore diameter, which is easier to prepare than other photonic crystal fibers with complex pore structure. Due to the advantages of high extinction ratio, extremely short beam splitting function and simple structure, the designed polarization beam splitter will be widely used in all-optical networks and optical device preparation.

Simple structure dual-core photonic crystal fiber polarization beam splitter covering the O + E + S + C + L + U band based on the surface plasmon resonance effect

In this paper, a simple structure dual-core photonic crystal fiber (SS-DC-PCF) polarization beam splitter (PBS) based on the surface plasmon resonance (SPR) effect and symmetric dual-core coupling mode theory is proposed. For the proposed SS-DC-PCF-1 PBS, the coupling lengths (CLs) and coupling length ratio (CLR) are analyzed, and the variations of the normalized output powers with the propagation length are investigated for the chosen wavelengths 1.434, 1.451, and 1.469 µm. The extinction ratio in cores A and B are compared at the three splitting lengths (SLs) 170, 173, and 176 µm. When the optimal SL is 176 µm, the splitting bandwidth (SB) is 255 nm (1.437–1.692 µm), and the insertion loss (IL) is less than 0.043 dB. The regulations of the CLs and CLR with the change of the structure parameters are analyzed. For the proposed SS-DC-PCF-2 PBS, the optimal SL is 232 µm, the SB is 201 nm (1.249–1.450 µm), and the IL is less than 0.042 dB. Finally, it is demonstrated that the total SB of the proposed SS-DC-PCF-1 PBS and SS-DC-PCF-2 PBS is 443 nm (1.249–1.692 µm), which can cover theO+E+S+C+L+Uband, even if the gold film thickness changes by±1nm. The proposed SS-DC-PCF PBS has excellent performances, such as ultrashort SL, ultrawide SB, ultralow IL, and good error-tolerance rate. It will have important applications in all-fiber optical systems.

Dual-core photonic crystal fiber polarization beam splitter filled with salt water

A dual-core photonic crystal fiber polarization beam splitter filled with salt water in the central ellipse is designed and optimized by the full-vector finite element method. For a polarization beam splitter length of 31.1245 μm, the orthogonally polarized light with a bandwidth of 180 nm around 1.55 μm can be separated effectively and the extinction ratio (ER) is 139.88 dB. The photonic crystal fiber polarization beam splitter offers advantages such as the short length, high ER, and broadband characteristics and have large potential in optical communication.

Ultra-short dual-core GaAs photonic crystal fiber splitter filled with nematic liquid crystal

A simple nematic liquid crystal-filled dual-core photonic crystal fiber polarization beam splitter is designed and analyzed by the full-vector finite element method. The length of the polarization beam splitter is 13.3390 μm and the maximum extinction ratio (ER) is 143.49 dB. The bandwidth of ERs greater than 10 dB is 200 nm at a wavelength of 1.55 μm. This simple and easy-to-manufacture structure has great potential in miniaturized communication devices.

An ultrashort length and high extinction ratio polarization beam splitter based on dual-core PCF

A novel dual-core photonic crystal fiber polarization beam splitter with high extinction ratio and ultrashort length is proposed. The effects of geometrical parameters of the DC-PCF on propagation performances are analyzed via finite element method. Numerical results demonstrate that the coupling length ratio of proposed polarization beam splitter can reach 1.997, and 420-µm-long physical length can also be obtained at the wavelength of 1.55 µm. High extinction ratios can reach − 54.43 dB, 69.09 dB and − 43.48 dB at the wavelengths of 1.37 µm, 1.55 µm and 1.68 µm, respectively. Furthermore, the bandwidths of high extinction ratios higher than 20 dB and 10 dB are about 33 nm and 96 nm at the wavelength of 1.55 µm. Considering the fabrication, the design has been simplified in order to reduce the difficulty of fabrication compared with complex designs, which is expected to have broad applications in optical devices field.

A Novel Gold Film-Coated V-Shape Dual-Core Photonic Crystal Fiber Polarization Beam Splitter Covering the E + S + C + L + U Band.

In this paper, a novel gold film-coated V-shape dual-core photonic crystal fiber (V-DC-PCF) polarization beam splitter (PBS) based on surface plasmon resonance effect is proposed. The coupling lengths of the X-polarization (X-pol) and Y-polarization (Y-pol) and the corresponding coupling length ratio of the proposed V-DC-PCF PBS without gold film and with gold film are compared. The fiber structure parameters and thickness of the gold film are optimized through investigating their effects on the coupling lengths and coupling length ratio. As the propagation length increases, the normalized output powers of the X-pol and Y-pol of the proposed V-DC-PCF PBS at the three wavelengths 1.610, 1.631, and 1.650 are demonstrated. The relationships between the extinction ratio (), insertion loss () and wavelength for the three splitting lengths () 188, 185, and 182 are investigated. Finally, it is demonstrated that for the proposed V-DC-PCF PBS, the optimal is 188 , the of the X-pol and Y-pol are less than 0.22 dB, and the splitting bandwidth () can cover the E + S + C + L + U band. The proposed V-DC-PCF PBS has the ultra-short , ultra-wide , and ultra-low , so it is expected to have important applications in the laser, sensing, and dense wavelength division multiplexing systems.

Ultra-short and dual-core photonic crystal fiber polarization splitter composed of metal and gallium arsenide

Two ultra-short polarization beam splitters (PBSs) based on surface plasma resonance (SPR) are designed for wavelengths of 1.31 and 1.55 μm. The center of the PCF has an oval hole filled with gold and the first layer of the air holes around the core is filled with the nematic liquid crystal (NLC) to enhance birefringence. In this work, the full vector finite element method is used to optimize the structural parameters. Two sets of parameters with extinction ratios of 114.02 and 111.86dB and lengths of 14.52328 and 11.02418μm are designed at wavelengths of 1.31 and 1.55 μm respectively. The results reveal that the beam splitters with broadband and short fiber length have important prospects in communication applications.

Numerical Investigation of a Short Polarization Beam Splitter Based on Dual-Core Photonic Crystal Fiber with As2S3 Layer.

A polarization beam splitter is an important component of modern optical system, especially a splitter that combines the structural flexibility of photonic crystal fiber and the optical modulation of functional material. Thus, this paper presents a compact dual-core photonic crystal fiber polarization beam splitter based on thin layer As2S3. The mature finite element method was utilized to simulate the performance of the proposed splitter. Numerical simulation results indicated that at 1.55 μm, when the fiber device length was 1.0 mm, the x- and y-polarized lights could be split out, the extinction ratio could reach −83.6 dB, of which the bandwidth for extinction ratio better than −20 dB was 280 nm. It also had a low insertion loss of 0.18 dB for the x-polarized light. In addition, it can be completely fabricated using existing processes. The proposed compact polarization beam splitter is a promising candidate that can be used in various optical fields.

Surface plasmon resonance-based silicon dual-core photonic crystal fiber polarization beam splitter at the mid-infrared spectral region

In this paper, a novel silicon dual-core photonic crystal fiber (Si-DC-PCF) polarization beam splitter (PBS) based on the surface plasmon resonance effect is proposed. The mode-coupling characteristics between theX- andY-polarized even and odd modes and surface plasmon polariton mode are analyzed by using the finite-element method and coupled-mode theory. The influences of the structure parameters of the Si-DC-PCF on the coupling length and coupling length ratio are investigated. The normalized output power of theX- andY-polarized modes in cores A and B and the corresponding extinction ratio are also discussed. By optimizing the structure parameters of the Si-DC-PCF, the PBS length of 192 µm and bandwidth of 830 and 730 nm in cores A and B are achieved. It is believed that the proposed Si-DC-PCF PBS can find important applications in mid-infrared laser and sensing systems.

A dual-core PCF polarization splitter with five elliptical air holes based on tellurite glass

A new kind of dual-core photonic crystal fiber polarization splitter based on tellurite glass is designed by introducing five elliptical air holes and octagonal lattice into the polarization splitter. The full vector finite element method and coupled-mode theory are used to study its characteristics. The structure parameters are optimized through the study of all parameters in the split structure. The results show that a polarization splitter with a short length of 105.156 μm can completely separate the two beams of polarization lights. And at the wavelength of 1.550 μm the extinction ratio can reach 124.920 dB. Meanwhile, the bandwidth is 165 nm when the extinction ratio is more than 20 dB and the wavelength range is from 1.467 to 1.632 μm, which covers the S + C + L wavelength bands. The bandwidth is 448 nm when the extinction ratio is more than 10 dB and the wavelength range is from 1.322 to 1.770 μm. The polarization splitter has a short length and a high extinction ratio and a wide bandwidth, which can be widely applied in large-capacity and integrated optical communication systems.

Design of a novel multi channel photonic crystal fiber polarization beam splitter

A kind of multi channel dual-core photonic crystal fiber polarization beam splitter is designed. We analyze the effects of the lattice parameters and the thickness of gold layer on the beam splitting by the finite element method. Numerical results show that the thickness of metal layer and the size of the air holes near the fiber cores are closely linked with the nature of the polarization beam splitter. We also obtain that extinction ratio can reach −73.87 dB at 1.55μm wavelength and at 1.41μm, 1.65μm extinction ratio can reach 30.8978 dB and 31.1741 dB, respectively. The comparison of the effect on the characteristic of the photonic crystal fiber with coating no gold is also taken into account.

Dual-core photonic crystal fiber polarization splitter based on lead silicate glass

A dual-core photonic crystal fiber (PCF) polarization splitter based on lead silicate glass is proposed. The characteristics of the polarization splitter are analyzed using full-vector finite element method. Compared with the silica glass PCF polarization splitter with the same structure, it is shown that the new material polarizer can realize splitting with less coupling loss and higher extinction ratio. When the wavelength is 1 550 nm and the PCF length in the beam splitter is 688 μm, the coupling loss is only 0.001 9 dB, and the extinction ratio for the input core is −64.1 dB.

基于碲酸盐玻璃的新型双芯光子晶体光纤偏振分束器

基于碲酸盐玻璃的新型双芯光子晶体光纤偏振分束器