<![CDATA[ IEEE Photonics Technology Letters - new TOC ]]>
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TOC Alert for Publication# 68 2016October 20<![CDATA[Electrowetting Lenticular Lens for a Multi-View Autostereoscopic 3D Display]]>282224792482641<![CDATA[Polarization-Maintaining Large Mode Area Fiber Design for 2- $mu text{m}$ Operation]]>${mu }text{m}$ operation, are studied. A commercial PM-PCF optimized for 1-${mu }text{m}$ operation has been scaled to obtain an 80-${mu }text{m}$ -diameter core, and then numerically analyzed with the help of a finite-element method-based software to investigate its behavior at different values of bending radius. From the problems emerged by this design, a new optimized design has been proposed and numerically simulated. The new fiber consists in a thulium-doped 19-cell core with a diameter of 80 ${mu }text{m}$ . The holes lattice, which follows the stack-and-draw scheme, has been modified to include two boron-doped stress applying parts, in order to induce a consistent birefringence. The results show that it is possible to achieve a single mode, single polarization operation, efficiently suppressing one of the fundamental mode (FM) polarization and the most significant higher order modes, in a range of bending radius from 33 to 40 cm. A remarkable value of 2600 ${mu }text{m}^{2}$ has been registered for the effective area of the survived FM polarization.]]>282224832486829<![CDATA[Multipoint Remote Methane Measurement System Based on Spectrum Absorption and Reflective TDM]]>2822248724901051<![CDATA[Depth-of-Focus Determination for Talbot Lithography of Large-Scale Free-Standing Periodic Features]]>2822249124945399<![CDATA[Avalanche Breakdown Characteristics of Al<sub>1–<italic>x</italic></sub>Ga<sub><italic>x</italic></sub>As<sub>0.56</sub>Sb<sub>0.44</sub> Quaternary Alloys]]>1–xGa_{x}As_{0.56}Sb_{0.44} quaternary alloys. Using p-i-n diodes with a 100-nm i—region and alloy composition ranging from $x=0$ to 0.15, we found that the bandgap energy of Al_{1–x}Ga_{x}As_{0.56}Sb_{0.44} reduces from 1.64 to 1.56 eV. The corresponding avalanche breakdown voltage decreases from 13.02 to 12.05 V, giving a reduction of 64.7 mV for every percent addition of Ga. The surface leakage current was also found to be significantly lower in the diodes with $x=0.10$ and 0.15 suggesting that Ga can be added to reduce the surface leakage current while still preserving the lattice match to InP substrate. The data from this letter can be downloaded freely.]]>282224952498807<![CDATA[Chaotic Encryption Algorithm Against Chosen-Plaintext Attacks in Optical OFDM Transmission]]>$10^{194}$ by using a 4-D hyperdigital chaos. The transmission of 8.9-Gb/s 16-QAM encrypted OOFDM data is demonstrated over 20-km standard single-mode fiber. The proposed encryption scheme provides excellent confidentiality of OOFDM transmission against the brute-force attacks and CPAs.]]>2822249925024363<![CDATA[Electro-Optic Property of Er<sup>3+</sup>-Doped LiNbO<sub>3</sub> Single Crystal for Integrated Optics]]>3+-doping effect on electro-optic property of LiNbO_{3} crystal has been studied. A series of congruent LiNbO_{3} crystals homogenously doped with different Er^{3+} concentrations up to 2 mol% in melt were grown. Unclamped electro-optic coefficients ${r} _{13}$ and ${r} _{33}$ of these crystals were measured by Mach–Zehnder interferometry. The results show that both ${r} _{13}$ and ${r} _{33}$ reveal little dependence on Er^{3+} doping level. $r_{13}$ hardly changes in the studied Er^{3+} doping level range 0–2 mol% within the experimental error of 3%. $r_{33}$ reveals a degradation tendency with a rise in the Er^{3+} doping level, but the degradation is no more than 5% in the Er^{3+} doping level range studied. The small effect is consistent with previous result that the performance of an electro-optic device based on Ti^{4+}-diffused Er^{3+}-doped LiNbO_{3} waveguide is not influenced noticeably by Er^{3+}-doping. A qualitative, comprehensible explanation is given for the small effect.]]>282225032506544<![CDATA[Radial Basis Function Neural Network Nonlinear Equalizer for 16-QAM Coherent Optical OFDM]]>$K$ -means clustering algorithm and the output layer weights are updated using the least mean square algorithm. With only 3% overhead in training, the proposed RBFNN-NLE was found to provide up to 4-dB performance improvement in terms of $Q$ -factor for 70-Gb/s 16-QAM CO-OFDM transmission over 1000 km ($10times 100$ km) fiber. Numerical results show that the operating data rate is 80 Gb/s at $Q = 6.25$ dB with the proposed RBFNN-NLE, compared with previously reported value of 70 Gb/s with artificial neural network-based NLE.]]>2822250725107628<![CDATA[A Modif ied Adaptive DBP for DP 16-QAM Coherent Optical System]]>$gamma _{mathrm{ opt}}$ and achieve comparable or even better performance than the DBP with full knowledge of fiber. Moreover, the proposed A-DBP can achieve better performance compared with the previous A-DBP based on intensity variance. Moreover, the proposed A-DBP requires fewer iterations to determine $gamma _{mathrm{ opt}}$ compared with the previous A-DBP based on intensity or phase variance.]]>282225112514830<![CDATA[An FIR Filter Using Segmented Photodiodes for Silicon Photodiode Equalization]]>$LC$ ladder network for its delay cells, where each segmented photodiode constitutes the ladder network. The measurement results show that the three-tap high-pass FIR filter incorporating segmented photodiodes designed for maximum bandwidth equalization achieves a bandwidth improvement of 7.4 times compared with that of a photodiode without segmentation and filtering. The upper bound of the equalization frequency of the three-tap high-pass FIR filter designed in this letter for maximum peaking frequency equalization is 14 times of the photodiode bandwidth.]]>2822251525181060<![CDATA[94-Gb/s 4-PAM Using an 850-nm VCSEL, Pre-Emphasis, and Receiver Equalization]]>282225192521557<![CDATA[SNSPDs on a Magnesium Fluoride Substrate for High System Efficiency and Ultra-Wide Band]]>2) substrate with the aim of producing a high system efficiency (SE) and wideband. The proposed SNSPD on a MgF_{2} substrate could simultaneously provide: 1) low lattice mismatching of the lattice constant between MgF_{2}and superconducting niobium nitride (NbN) films; 2) a low reflection loss (${n}=1.37$ ); and 3) a wide transmission band (0.2–$7~mu text{m}$ ). Based on the designed structure, a simulation indicated that the maximum absorption efficiency of the designed SNSPD on the MgF_{2} substrate is 97%. An SE of 46% at 1064 nm was measured without maximizing the polarization. The SNSPD on the MgF_{2} substrate was examined in a long-haul laser ranging application over four months, expanding the possibilities for application such as for laser ranging of space debris.]]>282225222525817<![CDATA[High Fill-Factor 4H-SiC Avalanche Photodiodes With Partial Trench Isolation]]>$150~mu text{m}$ , its fill factor can increase from 33.9% to 63.5% compared with the traditional full trench isolation structure. The photocurrent of the APD shows corresponding improvement when illuminated with the same UV light source. Through current–voltage, spectral response, and single photon detection characterizations, it is proved that the performance of the partial trench isolation APD does not degrade compared with the traditional full trench isolation structure. The APD fabricated in this letter with partial trench isolation shows a unity-gain peak quantum efficiency of 66.4% at 270 nm and a single photon detection efficiency of 9.5% at 280 nm when the dark count rate is fixed at 1 Hz/$mu text{m}^{2}$ .]]>282225262528814<![CDATA[The Anomaly of Periodicity Doubling in Projection Photolithography of Periodic Features]]>$pi $ -phase-shifted image were synchronously captured to generate the overlapped pattern with doubled periodicity within the depth-of-focus (DOF) area. The Fresnel diffraction theory was used to further derive the relationship between the mask and the objective lens’ parameters (i.e., the resolution and DOF). Finally, experimental results showed the self-image and $pi $ -phase-shifted image, both clearly recorded on wafer when optical parameters were well adjusted.]]>282225292532955<![CDATA[Low Loss Fiber-to-Waveguide Converter With a 3-D Functional Taper for Silicon Photonics]]>2 taper for silicon photonics. The converter is composed of a cantilevered SiO_{2} waveguide and Si nano-tapers. In order to reduce the loss from the cleaved fiber, a 3-D functional SiO_{2} taper is designed to compress the size of optical mode field. Using cleaved optical fibers with a mode field diameter of 10.5 $mu text{m}$ at 1550 nm, we characterized the optical performances of the converter. With an index-matching liquid, the lowest coupling loss of TE mode is 1.5 dB/facet and the lowest coupling loss of TM mode is 2.1 dB/facet. For both TE and TM modes, the 1-dB bandwidth is more than 100 nm, and the alignment tolerances for 1-dB excess loss are, respectively, ±2.5 and $pm 2~mu text{m}$ in horizontal and vertical directions.]]>2822253325361513<![CDATA[Effects of Electrical and Optical Equalizations in 28-Gb/s RSOA-Based WDM PON]]>${N}$ -ary pulse-amplitude-modulation (PAM) format. The results show that the optical equalization is capable of compensating the waveform distortions caused by both the bandwidth-limitation of RSOA and fiber’s chromatic dispersion without deteriorating the signal-to-noise ratio (SNR). On the other hand, the electrical equalization is effective for the compensation of the bandwidth-limitation of RSOA only at the cost of SNR. The results also show that the electrical equalization is helpful to compensate for the remaining waveform distortions after the optical equalization. By using both equalizers, we demonstrate the transmission of the 28-Gb/s signals in polar RZ-PAM-${N}$ formats (${N} =2$ , 3, and 4) over 20 km of standard single-mode fiber.]]>2822253725401462<![CDATA[Analog Pre-Distortion Circuit for Radio Over Fiber Transmission]]>2822254125441028<![CDATA[Broadband, Polarization-Insensitive, and Wide-Angle Optical Absorber Based on Fractal Plasmonics]]>2822254525481070<![CDATA[Hybrid Integration With Efficient Ball Lens-Based Optical Coupling for Compact WDM Transmitters]]>$4times25$ -Gb/s compact wavelength-division multiplexed transmitter with low coupling losses of $sim 2$ dB between lasers and a planar lightwave circuit multiplexing filter.]]>282225492552589<![CDATA[Effective Mode Field Diameter for LP<sub>11</sub> Mode and Its Measurement Technique]]>11) mode in two-mode fibers is determined to allow estimation of the coupling efficiencies at a splice with axial misalignment. Simulations are performed to verify its validity. In addition, we propose a novel technique for measuring the effective MFD distribution for the LP_{11} mode along two-mode fibers. The technique is based on optical time-domain reflectometry; it conducts measurements in the two-mode region of test fibers and individually observes the LP_{01} and LP_{11} modes of the backscattered light. Its feasibility is demonstrated experimentally.]]>282225532556734<![CDATA[Temperature Sensing Characteristics Based on Up-Taper and Single Mode–Multimode Fiber Structure]]>$^{circ }text{C}sim 80~^{circ }text{C}$ can be achieved. The sensor has a series of advantages, such as high sensitivity, low cost, compact size, and reflective measurement.]]>282225572560864<![CDATA[Carrier Phase Estimation Based on Error Function Calculation for 16-QAM Systems]]>$-pi $ /4, $-pi $ /8, 0, and $pi $ /8) to directly calculate the optimal phase angle, which effectively reduces the computational complexity compared with the blind phase search algorithm. Next, we combine the proposed CPE algorithm with an improved V&V algorithm and propose a two-stage CPE algorithm, which has both advantages of good linewidth tolerance and low computational complexity. Through simulations, the effectiveness of the proposed algorithms is demonstrated in a 28-Gbaud 16-QAM coherent optical transmission system.]]>2822256125641242<![CDATA[WGM Micro-Fluidic-Channel Based on Reflection Type Fiber-Tip-Coupled Hollow-Core PCFs]]>$8.65 times 10^{mathrm { {4}}}$ has been experimentally acquired at $sim 1557.75$ nm. Theoretical simulation results indicate that the refractive index sensitivity of the whispering-gallery-mode resonance wavelength reaches 1259.9211 nm/RIU for biocompatible low refractive index range. The proposed microfluidic detection platform has a few desirable merits, such as ease of fabrication, low-cost, and structure robustness, which ensures its applicability for practical use in chemical as well as biological sensing applications.]]>2822256525681155<![CDATA[A Practical FBG Sensor Based on a Thin-Walled Cylinder for Hydraulic Pressure Measurement]]>$0sim 16$ MPa. Compared with other references, the proposed pressure sensor in this letter is more compact with good sensitivity and wide measurement range.]]>2822256925722424<![CDATA[A Laser-Based Fiber Bragg Grating Ultrasonic Sensing System for Structural Health Monitoring]]>2822257325761579<![CDATA[Brillouin Optical Time Domain Analysis in Silica Fibers at 850-nm Wavelength]]>$sim 19$ 795 and 90 MHz, respectively. The estimated peak Brillouin gain is $ {0.32} ,,,{ {(mW)}}^{{-1}}$ . The temperature and strain dependences of BFS were determined as well. Distributed sensing capability was demonstrated at a minimum spatial resolution of 1.5 m and a fiber length of 100 m. As a proof-of-principle, the temperature and strain dependences of the BFS in SFM-28 fiber have been determined at 850- and 1550-nm wavelengths, suggesting its possible use for temperature/strain discrimination.]]>282225772580883<![CDATA[Polarization-Independent Plasmon-Induced Transparency in a Symmetric Metamaterial]]>2822258125841035<![CDATA[Coherent Beam Combining of a Fiber Lasers Array Based on Cascaded Phase Control]]>$lambda $ /28, and then, the combined beams from the two sub-arrays are phase locked by using a single-frequency dithering technique with a residual phase error of $lambda $ /24. It is scalable to phase lock of hundreds of fiber lasers, because high control bandwidth can be obtained by using cascaded phase control.]]>282225852588928<![CDATA[Digital Nonlinear Compensation for Spectrally Sliced Optical Receivers With MIMO Reconstruction]]>$20times56$ -GBd 400 G WDM transmission system, different approaches for nonlinear compensation in spectrally sliced optical receivers with MIMO-based signal reconstruction. Slice-by-slice nonlinear compensation shows comparable performance to inter-slice nonlinear compensation in a WDM system. In addition, an eight-stages compensation yields a 0.4-dB Q^{2} gain equivalent to 250-km distance increase, resulting in 2000-km transparent reach.]]>282225892592725<![CDATA[MIMO Transceiver Design in Dynamic-Range-Limited VLC Systems]]>282225932596490<![CDATA[Mode Splitter Without Changing the Mode Order in SOI Waveguide]]>0 and TE_{1} modes without changing the mode order. It is found that high coupling efficiency (higher than −1 dB), low mode crosstalk (less than −16 dB), wide bandwidth ($sim 100$ nm), and large fabrication tolerance (±10 nm) can be obtained by a $24.4~mu text{m}$ coupling length DC structure, which is composed of a strip and a slot silicon waveguide. This design represents a first step toward mode splitter without changing the mode order, which can find important potential applications, such as optical isolation and mode division multiplexing (MDM), in large-scale photonic integrated circuits (PICs).]]>2822259726001733<![CDATA[Flexible TE-Pass Polymer Waveguide Polarizer With Low Bending Loss]]>2822260126041017<![CDATA[High-Efficiency Nanoplasmonic Wavelength Filters Based on MIM Waveguides]]>282226052608900<![CDATA[Highly Efficient Broadband Waveguide Adiabatic Polarization Converter With Apodization]]>282226092612891