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In this paper we propose a novel type of highly-birefringent and ultra-wideband low-loss photonic crystal fiber (PCF) incorporating elliptical holes in the cladding and rhombic holes located along the transversal axes. The PCF is simulated and analyzed with finite-difference time-domain method. The properties of PCFs were investigated for various distribution, shape and size of air holes. For the optimized PCF design the birefringence reaches 8 × 10−3 at 1550 nm and the confinement loss is as low as 5 × 1 0 − 4 dB/km with single mode operation in an ultra-broad transmission band (500 nm–1800 nm). Furthermore, the single mode and single polarization transmission could be achieved in this PCF at longer wavelengths beyond 1600 nm. This kind of PCF has potentials in optical long haul communication and optical fiber sensing.

We present the design and investigation of a single-polarization suspended-core fiber with an elliptical core consisting of crossed rectangular-shaped dielectric strips. By optimizing the fiber configuration parameters, single-polarization single-mode transmission with a bandwidth of 400 nm can be obtained. Also, the power fraction in air of the x-polarization fundamental mode is relatively high, which facilitates its applications in high precision sensors.

It is put forward that solar vector can be obtained with polarization sensors in this paper, which plays an important role as a great clue of navigation. First, the design of the polarization sensor is introduced with the extraction method of azimuth angle from the polarization pattern. Then, it is advanced that solar vector can be attained through observing different directions using one or two polarization sensors. Consequently, an experiment is conducted and the results indicate that both algorithms of measuring solar vector are feasible. For the method of measuring solar vector with two polarization sensors, the accuracy of solar azimuth angle is 0.2°(1σ), and the accuracy of solar elevation angle is 0.4°(1σ) approximately. By contrast, the accuracy is relatively low for the method of using single polarization sensor.

The wavelength-dependent polarization absorber based on multi-cladding fiber (MCF) with surface plasmon resonance (SPR) is proposed and demonstrated. In order to obtain the SPR effect both in the x- and y- polarized direction, the MCF is polished in two sides. The numerical simulations show that the polarization absorber with the wavelengths of 980/1550 nm and 1310/1550 nm can be obtained by adjusting the parameters of dielectric layer. Each wavelength only transmits a single polarization in the wavelength-dependent polarization absorber, and the loss of unwanted polarized mode is more than 95 dB/cm. In addition, when the length of fiber is only 550 µm, the bandwidths of polarization absorber are 29 nm at 980 nm and 413 nm at 1550 nm, respectively; meanwhile, the bandwidth of 1310/1550 nm polarization absorber reaches 102 nm and 302 nm, respectively.

A highly birefringent square lattice terahertz (THz) photonic crystal fiber (PCF) coated with epsilon-near-zero (ENZ) material and doped with gain material is proposed for single polarization propagation. Due to introduction of the ENZ rings into square lattice, the large loss difference between the x-polarization mode and all other modes is obtained. The loss of the x-polarization mode is compensated by doping the core area with gain material. The single polarization PCF obtains a loss difference better than 13.2 dB/cm in the frequency range of 0.960–1.307 THz (bandwidth of 0.347 THz). This proposed single polarization THz PCF has some potential applications in coherent THz communication or polarimetric fiber sensor systems.

A photonic crystal fiber (PCF) with nanoscale gold-coated and liquid-filled air-holes is proposed, which can realize anomalous single-polarization transmission. That is, the polarization filtering in the x- and y-polarization directions is achieved at wavelengths of 1.18 and 1.55 μm. The dispersion characteristics and losses of filter are analyzed by the finite element method (FEM). The results show that when the fiber length is 800 μm, the extinction ratios (ERs) at the above two wavelengths are 31.25 and -248.63 dB, and the corresponding bandwidths are 28 and 270 nm, from 1.165 to 1.193 μm and 1.43 to 1.70 μm, respectively. Furthermore, by changing the structural parameters, not only can the positions of resonance wavelengths in the two orthogonal polarization directions be changed simultaneously, but also the positions of resonance wavelengths in the x polarization direction can be changed singly, which is conducive to the filtering of PCF at a specific wavelength within a certain range.

To analyze the overlying strata movement law of recovering room mining standing pillars with solid backfilling. Physical simulation experiments with sponge and wood as the backfilling simulation material were tested. The results show that: (i) The covering-rock mechanics of the overly strata comes from “two-arch structures + hinged girder + bend beam” to “backfilling material + hinged girder + bent beam” by increasing the fill ratio from 0% to 85%, the beginning of overlying strata movement appears later and the total duration of subsidence velocity increased from zero to the highest value increases. The trend of “single polarization” of the subsidence velocity curves becomes noticeable and the velocity variation trend becomes stable. (ii) The equiponderate aeolian sand was added to improve the anti-pressure ability of the loess, and the corresponding ground processing & transportation system was designed. Keywords: Room mining standing pillars, Solid backfilling, Physical simulation experiment, Overlying strata movement

We present a design of a dual-core leaky waveguide that can be used as an integrated-optic polarizer. The proposed polarizer works on the principle of mode filtering. The structure is characterized by two cores, namely core-1 and core-2 and a high index layer in the upper-most region, such a structure supports leaky modes. The leakage losses of the modes have been calculated by using the transfer matrix method (TMM). Single polarization operation is ensured by high differential leakage loss between fundamental TE and TM modes. We show TE-pass operation with 0.5 dB/mm loss in TE 0 mode and 13 dB/mm loss in TM 0 mode, and TM-pass operation with 0.36 dB/mm loss in TM 0 mode and 7.45 dB/mm loss in TE 0 mode. Besides single-polarization operation, single-mode operation of the structure is ensured by high leakage loss of all the other higher-order modes.

We describe two schemes for 1.28 Tbit/s single-channel transmission at 640 Gbaud with polarization-multiplexed DPSK and single-polarization DQPSK, and compare their performance in a 500 km transmission. We found that the polarization multiplexing of ultrahigh-speed DPSK signals, for example at 640 Gbaud, is sensitive to the PMD characteristics of the transmission link. Even when first-order PMD is fully compensated, second-order PMD, which varies over a long period and is difficult to compensate, results in inter-polarization crosstalk induced by depolarization. The single-polarization transmission of a 640 Gbaud DQPSK signal is less vulnerable to PMD and therefore more stable, as the depolarized components induced by second-order PMD can be easily rejected with a polarizer. However, its performance is limited because the OSNR must be higher than for DPSK.

We proposed and demonstrated all-optical polarity- and shape-switchable ultrawideband (UWB) Gaussian pulses generation schemes using a single polarization interferometer (PI) or a semiconductor optical amplifier (SOA) cascaded by a PI. When an optical signal with dark return-to-zero (RZ) format propagates directly through a single PI, a pair of polarity-reversed UWB monocycle pulses and a positive UWB doublet pulse is acquired respectively only by adjusting the polarization controllers, without changing the bias of the intensity modulator. If a SOA is connected at the input of the PI to firstly implement the first-order differential function to the input dark RZ pulse utilizing gain saturation effect of the SOA, both polarity- and shape-switchable UWB Gaussian monocycle and doublet pulses are all acquired from the cascaded system. Moreover, if a nonreturn-to-zero control signal is introduced into the SOA, utilizing the cross-gain modulation (XGM) effect of the SOA and the differential characteristic of PI, all-optical shape modulation to UWB signals can be realized, and the polarity of the modulated UWB pulses can also be switched. Also, UWB signal transmission characteristics in fiber link were investigated.

We propose and analyze a novel design of single-polarization single-mode photonic crystal fiber based on index-matching coupling by using a finite-element method. The proposed fiber is designed such that there is a large differential loss between two polarizations of the fundamental mode by reducing two air holes in the cladding region which is composed of hexagonal structured air holes in pure silica. From the numerical analysis it is shown that single-polarization single-mode operation wavelength region can be tuned by adjusting the diameters of two defect air holes. In the proposed design, the spectral region over which the differential loss ratio is larger than 100 can be wider than 150 nm around the wavelength 1.55 or 1.31 μm. Another novel design that allows simultaneous single-polarization single-mode guidance in two wavelength windows centered at 1.55 and 1.31 μm is also proposed.

Stable single-frequency and single-polarization distributed-feedback (DFB) fiber laser was realized by giving a pressure on the phase shift region of the fiber grating. The output wavelength of the DFB fiber laser is 1053 nm. When the pump power of 980 nm laser diode is 100 and 254 mW, the output power can reach 8.3 and 37.1 mW and the polarization extinction ratio was 26 and 20 dB, respectively. After chopped by Acousto-optic modulator (0.3 Hz), the pulse peak value variance is 4.65%(peak to peak) and 1.098% (RMS) for 31 min.

One of the more recent developments in operational spaceborne remote sensing is the availability of radar. This sensor has the ability to penetrate through clouds making it a more easily available data set for some locations. In addition, radar interacts very differently with surface features than optical data providing information more related to shape and structure than composition. A disadvantage of currently available spaceborne radar is that the data are almost entirely single wavelength and single polarization limiting the ability to do traditional digital classification. This study examined the usefulness of radar-derived texture measures for feature identification. Texture measures were compared independently and in combination with the original radar for digital land cover delineation. The primary methodology was standard image processing spectral signature extraction and the application of a statistical decision rule to classify the surface features for several sites in East Africa and one in Nepal. Relative accuracy of the resultant classifications was established by digital integration and comparison to validation information derived from field visitations. Variance texture measures were found to be generally very advantageous over original radar values but quite variable in their delineation accuracies from one cover type to another.

Single-frequency and single polarization distributed-feedback (DFB) fiber laser by stress-induced phase-shift birefringence was demonstrated and the corresponding theoretical analysis was presented. The polarization extinction ratio of the DFB fiber laser is about 15 dB.

All-optical regeneration of 2 × 10-Gb/s RZ-OOK polarization-division-multiplexed (PDM) signals is demonstrated through a single polarization nonlinear loop mirror configuration. PDM signals with orthogonal polarization states are regenerated simultaneously and reassembled automatically. Up to 3.0-dB eye-diagram-based signal-to-noise-ratio (SNR) improvement is achieved for both channels with the input SNR of 6.7 dB. Such scheme is also capable of mitigating the polarization-mode-dispersion (PMD) effect for PDM signals in the presence of up to 6.3-ps DGD.

The single polarization observables Σ , P and T are presented for the reaction 3 He( γ , π + ) 3 H at various kinematics. The process is described in a recently developed nonlocal coupled-channel framework that employs three-body Faddeev amplitudes and incorporates two-step processes such as 3 He( γ , π 0 ) 3 He( π 0 , π + ) 3 H. Enhancement effects of the contributions from small components of the 3 He wave function as well as from the Δ-resonance E2 transition to the polarization observables have been found.

A set of coupled power equations derived from that of amplitude equations for single-polarization (SMSP) optical fibers has been presented. Our results show that the power coupling coefficients are related not only to the effect of the birefringence of SMSP fibers, but also to the leaky mode loss.

To measure the emf of cells containing metal and halogen electrodes in solutions of metal halides in fused organic salts, conventional halogen electrodes cannot be used because of reaction of the halogen with the organic salts. Consequently a method has been developed wherein the halogen is momentarily generated at unit activity by a single polarization impulse within the cell itself. The theory of the method is developed, and experiments with silver halides in alkylammonium halides demonstrate its validity.