Presents the table of contents for this issue of the publication.

In this letter, we propose a parallel dual-wavelength pumping (DWP) method (655 nm + 1981 nm) to realize high power output from a Er 3+ -doped ZrF 4 fiber laser at $\sim 3.5~\mu \text{m}$ , for the first time, to the best of our knowledge. This laser can emit a maximum power of 1.72 W, where the slope efficiency with respect to the launched 1981 nm pump is 31.5%. Further power scaling is mainly limited

The coherent temporal soliton in optical microresonators has attracted great attention recently. Here, we have fabricated the microrod resonator with Q factor as high as $2\times 10^{8}$ and demonstrated the dissipative Kerr soliton generation in such a microresonator, by utilizing an auxiliary-laser-assisted thermal response control. In addition, we have changed the pump laser and observed the perfect

We propose and experimentally demonstrate digitally programmable optical frequency combs (OFCs), featured by binary phase distribution and flat power envelope among comb lines for the first time. In the proposed simple generation scheme, a programmable optimized binary sequence is generated and applied to phase modulate a CW lightwave, creating an OFC with joint manipulation of both binary phase distribution

An ultralow- $\text{V}_{\pi }\text{L}$ photonic switch device is demonstrated utilizing the high optical and electrical field confinement in silicon slot waveguides coupled with the strong electro-optic response of nematic liquid crystals. A silicon photonic directional coupler switch with a modulation efficiency of 0.0195 $\text{V}\cdot $ mm and a loss-efficiency product of 0.0624 $\text{V}\cdot $

We investigate the scalability and performance of a novel optical wireless data center network (OW-DCN) based on passive diffractive optics and fast tunable transmitters. The proposed OW-DCN architecture consists of two parallel inter- and intra- cluster networks to implement a flat communication between the top of racks within the DCN with at most two hops. The proposed DCN operation, the transmission

An equivalent circuit model for a typical commercial light-emitting diode (LED) used in visible light communication (VLC) applications is proposed. The parameters of the elements in the model are extracted from the measured impedance using a vector network analyser. The model shows high accuracy in fitting the measured results and shows the effect of bonding/packaging parasitics and the electrostatic

We propose a method to continuously frequency shift a target laser that is frequency stabilized by a reference laser, which is several hundreds of nanometers detuned. We demonstrate the technique using the $\mathrm {5S_{1/2}} \rightarrow \mathrm {5P_{3/2}} \rightarrow \mathrm {29D_{5/2}}$ Rydberg transition in 87 Rb vapor and lock the 482 nm target laser to the 780 nm reference laser using the cascaded

We propose a surveillance system of fiber optic cables with multi-channel distributed acoustic sensing (DAS) interrogator equipped with optical rotary switch. By switching the optical connection between the interrogator and multiple optical fiber-under-test, we take samples of the sensed vibration signal from the fibers with single pulse generator and optical receiver. To identify the source of detected

We investigated an FPGA-based dual-pulse anti-interference light detection and ranging (LiDAR) system with digital chaotic pulse position modulation (DCPPM). The dual-pulse signal is a periodic pulse pair, in which the first pulse is a periodic pulse, and the second pulse based on DCPPM is a pulse with a random time interval from the first pulse in each period. The real-time generation and detection

A thin-disk multi-pass laser amplifier scheme with strong tolerance for variation of thin-disk thermal lensing is proposed and 213 W average output of 800 ps pulse is realized at a repetition rate of 200 kHz, with a pulse energy over 1 mJ. The amplifier was pumped by a commercial fiber coupled laser diode and seeded by a home-made thin-disk laser regenerative amplifier. The maximum magnification of

We demonstrated an ultra-broadband dual-polarization power splitter based on silicon subwavelength gratings (SWGs). Multimode interference (MMI) couplers based on SWG are utilized for power splitting. SWGs with different orientations are combined to form a taperized hetero-anisotropic slab, which contains single mode for TE light but multimode for TM light. Such configuration is utilized to make it

A photonic approach to generating an optoelectronic oscillator (OEO) based on an integrated mutually coupled (IMC) distributed feedback (DFB) laser is reported. Compared with the traditional construction of an OEO, the IMC-DFB has functions of the laser source, intensity modulator, and microwave photonic filters (MPFs), which could simplify the OEO scheme. An optical feedback loop (O-Loop) and an optoelectronic

For three-dimensional (3-D) measurement of dynamic objects, a new three-part phase unwrapping algorithm is proposed. First, a novel fringe modulation degree threshold estimation method is proposed. Then, the unwrapped phase can be obtained by three segments. The first-segment is calculated by 2-D spacial phase unwrapping algorithm while the fringe modulation degree is within the threshold. The second-segment

Tilted fiber Bragg gratings (TFBGs) have peaks in the transmission spectrum associated with cladding modes. The spectral distances between these peaks depend on the geometry of the optical fiber including the cladding, tilt angle and structure period. In this letter we propose to increase the number of peaks in the spectrum without changing the geometry of the optical fiber. Such effect can be achieved

In this study, we propose a centrifugation packaging (CP) structure to enhance the optical and thermal dissipation performance of LEDs, using SBA-15 particles to facilitate the sedimentation and dispersion of QDs. The results indicate that the EL spectra of the LEDs remains almost unchanged after the centrifugation time of 60 min and a CP structure can be obtained. The radiation power and luminous

We have numerically and experimentally studied an electro-optic Q-switched 1064 nm Nd:YVO 4 laser with sub-nanosecond output. An effective numerical model is demonstrated, in which the intracavity photon density and the population inversion density are defined as variables of temporal and spatial. Guided by the numerical results, the maximum 1064 nm output pulse energy of $275~\mu \text{J}$ has been

In this letter, the mixed finite element method (Mixed FEM) incorporating with the surface current boundary condition (SCBC) is firstly proposed to perform eigenmode numerical simulations of graphene-based plasmonic waveguides. The SCBC which is based on modeling graphene as the zero-thickness conductive sheet, is introduced to reduce the extremely fine discretization of graphene at the atomic scale

A specially designed InP semiconductor optical amplifier (SOA) is flip-chip bonded to the silicon-on-insulator photonic circuit, in which only horizontal alignment is involved reducing the complexity of integration and light is evanescently coupled to the silicon waveguide from the SOA. Two groups of slots are applied as two high-order Distributed Bragg Reflectors (DBR) to select a single mode in the

We demonstrate a technique of evaluating optical signal to noise ratio (OSNR) associated with an optical carrier in a fiber-optic system using a commercial coherent optical transceiver equipped with digital signal processing capability. The procedure of measuring noises caused by the transmitter and the receiver is outlined, and these transceiver-related noises need to be taken into account in order

We first present a bidirectional beam propagation method (BiBPM) based on axially symmetric full-vectorial finite element method (Axi-FVFEM). The Axi-FVFEM based BiBPM is a more versatile method than previous scalar BiBPM for axi-symmetric structure. It has potential to offer more efficient analysis than widely used FEM or finite difference based techniques, especially for a large scale waveguide such

A cascaded Fabry-Perot interferometers (FPIs) structure based on polymer-air cavities is proposed and demonstrated. The structure can be easily manufactured by inserting a section of single-mode fiber (SMF) with a flat end-face into the silica capillary tube (SCT), then filling the SCT with polymer under capillary action, and last inserting another segment of SMF from the other end of the SCT. Thus

In this study, a novel and simple optical fiber sensor is proposed, simulated, and experimentally demonstrated for simultaneous measurement of high refractive index (RI) and temperature. The sensor consists of a section of single-mode-silica rod-single-mode (SSRS) fiber structure cascaded to fiber Bragg grating (FBG) (SSRS-FBG). The simultaneous measurement of high RI and temperature was realized in

We demonstrate an optically pumped vertical external-cavity surface-emitting laser (VECSEL) based on quantum dots (QDs) with a high optical gain. The photoluminescence (PL) emission of the QDs at the operating wavelength of 1030 nm has been optimized towards a high integrated intensity by using a dot density in the range of 10 11 cm −2 and a narrow PL linewidth of around 30 meV due to an improved size

Single-mode fiber coupler with variable coupling ratio is a flexible tool for optical fiber applications. Here we demonstrate a microfiber based coupler with compact size and wide tuning range. The coupler consists of two identical single-mode microfibers that are fabricated via parallel pulling process. By adjusting the twisting angle between these microfibers, the coupling ratio varies from 3.15%

This letter reports a PCDTBT: PCBM: CdSe tetrapod shaped nanocrystals (NCs) nanocomposites based hybrid inorganic-organic ultraviolet (UV)-Visible (Vis) photodetector fabricated on fluorine-doped tin oxide (FTO) coated glass substrate. The tetrapod shaped nanocrystals synthesized by solution method are mixed with PCDTBT: PCBM to achieve the desired nanocomposites for the active layer of the device

Dual-wavelength light source assisted frequency response measurement of photodetectors based on double-sideband suppressed-carrier modulation is proposed in this letter. In this method, a directly modulated laser with a modulation frequency of $f_{1}$ combined with an optical tunable filter is used to generate a dual-wavelength carrier, which can be highly stable since only one light source is introduced

We report a 16.8 Tb/s true random number generator (TRNG) based on amplified spontaneous emission (ASE) of Erbium-doped fiber amplifier (EDFA), which is sliced into 42 parallel channels by an arrayed waveguide grating (AWG). The true randomness of ASE is enhanced and guaranteed by a novel extraction approach utilizing two orthogonal polarized components of ASE. Consequently, the random number generation

Based on the unique polarization characteristic of the cylindrical vector beam, a new-type vector magnetic field sensing technique is proposed. As the cylindrical vector beam passes through a magnetic fluid film, a polarization analyzer is used to detect the polarization state change of the output light after passing through a slit. Based on the birefringence effect, the direction of the magnetic field

We propose and demonstrate a type of highly efficient tunable Mach-Zehnder interferometer (MZI) in Z-cut lithium niobate thin film (TFLN) based on the thermo-optical effect. By placing the electrode directly above the TFLN waveguide, a more uniform and higher heat distribution was obtained, compared with the conventional horizontal structure. Both the principle and design strategies of the proposed

A photonic crystal fiber was selectively infiltrated only two of the air holes near the core with liquid crystal. The selective infiltration caused geometric asymmetry and created high birefringence. Because of the geometric asymmetry, the response to varying electric field is concerned with electric field direction. A Sagnac interferometer was set to investigate the electric tuning characteristics

Nanostructures with the ability to efficiently generate colors in visible range attract lots of attention. Current plasmonic materials-based techniques always require complicated lithographic processes, which are expensive and severely limiting the production throughput. In this letter, we experimentally demonstrate a large-area silicon-based multilayer structure for color filtering. The designed lithography-free

This letter presents a novel narrow-band bandpass spoof surface plasmon polarition (SSPP) filter, which has a controllable passband, good rejection, and a compact structure. It is composed of two end-extending SSPP transmission lines and a pair of L-shaped coupling branches. Both the bandwidth and the central frequency can be adjusted by changing the depth of the SSPP unit and the length of SSPP transmission

We report on the realization of a novel fiber-optic radio frequency (RF) transfer scheme with the bidirectional frequency division multiplexing (FDM) dissemination technique. Here, the proper bidirectional frequency map used in the forward and backward directions for suppressing the backscattering noise and ensuring the symmetry of the bidirectional transfer RF signals within one telecommunication

We propose and demonstrate a fabrication-friendly on-chip polarizer based on polarization-selective corner mirrors. The total internal reflection angles are distinct between TE and TM modes due to the strong birefringence of silicon-on-insulator (SOI) waveguide. Thus, by properly choosing the inclination angle, TE mode can be completely reflected at each corner mirror with negligible losses, whereas

Transverse mode instability (TMI) is one of the main limitations for the power scaling of high-power fiber lasers. In order to suppress TMI and increase the output power of the fiber laser, we demonstrated a novel strategy by shifting the center wavelength of the pump source, i.e., laser diodes (LDs), from conventional 976 nm to the optimized 981 nm. A fiber oscillator is built to investigate the TMI

With the objective of enabling wide tuning characteristics of a semiconductor light source for CO 2 gas sensing, we demonstrate a 2.0- $\mu \text{m}$ wavelength superstructure grating (SSG-) DBR laser for the first time. SSGs for the 2.0- $\mu \text{m}$ wavelength with seven reflection peak characteristics were designed and introduced to a DBR laser with strained InGaAs multi-quantum-wells (MQWs).

We demonstrate the detection of speech signals and footsteps through a novel polarization-multiplexed coded differential-phase OTDR (optical time domain reflectometry) interrogation of standard telecom fibers in different configurations. We assess the sensitivity to audio signals by measuring the induced phase variation with respect to the sound pressure level of the perturbation, and manage to detect

A silent failure is a kind of failure that existing optical devices or equipment cannot detect although the failure actually happens. This failure makes it more difficult for maintenance operators to identify the fault point, which potentially deteriorates the reliability of the network. To address this issue, we propose a unique silent failure localization method using characteristic information obtained

Stress birefringence (SBR) of optical components is significant in polarization-dependent and fine optical applications, such as optical lithography. However, the methods generally used for high-resolution birefringence distribution detection are unsuitable for measuring samples with nonplanar surfaces, such as lenses, owing to refraction and aberration. In this work, we propose and verify a method

Vertically aligned zirconium dioxide (ZrO 2 ) nanowire (NW) array based fast response ultraviolet (UV) detector has been fabricated upon ZrO 2 thin film (TF) by glancing angle deposition (GLAD) technique. The detector shows ~1.4 fold lesser dark current and ~1.5 fold enhanced light current than the ZrO 2 TF due to the formation of oxygen vacancies. Improved detector performances through ~1.8 fold high

We report a high-power source of continuous-wave (cw) mid-infrared (mid-IR) radiation at 2.26 $\mu \text{m}$ based on difference-frequency-generation (DFG) of a cw Yb-fiber laser at 1.064 $\mu \text{m}$ and a cw Tm-fiber laser at 2.010 $\mu \text{m}$ in MgO:PPLN. Using a 50-mm-long crystal with a single grating period of 32.16 $\mu \text{m}$ and a simple single-pass setup, we generate up to 3.84 W

We demonstrate the laser performance of a LD end-pumped Er:YSGG crystals with different doping concentrations comparatively. The experimental results show that 30 at. % Er:YSGG crystal with dimensions of 2 mm $\times2$ mm $\times8$ mm has the best laser output. In continuous-wave (CW) mode and pulse mode, the maximum output powers of 1.37 and 1.20 W are achieved, corresponding to slope efficiencies

A novel real-time interrogation technique based on an SMF-TMF-SMF (STS) structure and wavelength-to-time (WTT) mapping is proposed and experimentally demonstrated. An ultrashort optical pulse is first spectrally shaped by the homemade STS comb filter, which is formed by inserting a section of two-mode fiber (TMF) into single-mode fibers (SMF) using core-offset splicing. Linear WTT mapping is realized

In this letter, we propose a novel bamboo-shaped interference sensor based on multistage photonic-band gap microstructured fiber (PBG-MF) and single-mode fiber (SMF) to build the cascaded Fabry-Perot interferometer (FPI). Due to the honeycomb space inside the PBG-MF, a higher extinction ratio (ER) is obtained in the reflection spectrum of the interferometer, which is conducive to improving the detection

In mobile optical camera communication (MOCC) system, more than one LED is used to simultaneously illuminate and communicate. In the letter, the MOCC system with multi-LEDs and a mobile receiver is experimentally investigated. To avoid the signal interference between two LEDs and alleviate the performance degradation caused by the movement of the receiver, multi-column matrices selection (MCMS) combined

This work proposes using the changes in the LEDs’ spectral emission induced by temperature variations to implement emitters for new communication channels in Optical Camera Communication (OCC) systems. If a camera can discriminate the shift in LEDs’ spectral response, these modifications can be contemplated as a new data channel. The main advantage is that new channels can be obtained from the same

Featuring extraordinarily curved propagation trajectories, self-accelerating Airy beams have stimulated considerable interests from academic research to practical applications. However, generation of high-quality Airy beams using compact optical devices is still highly desirable. Here we present a design of integrated Airy phase plates (IAPPs) with a miniature size ( $60\,\,\mu \text{m}\,\,\times 60\

In this letter, we demonstrate a high-sensitivity flow rate sensor which is packaged using a stable and convenient method. The sensor is based on an optofluidic microbottle resonator (OFMBR), which serves as a promising platform for fluid sensing due to its ultrahigh quality factor and inherent microfluidic channel. The coupling system is packaged using a modified method, and the sensor’s stability

A monolithic thin film red light emitting diode (LED) active-matrix (AM) micro-display driven by a complementary metal-oxide semiconductor (CMOS) driver is demonstrated. The resolution of the micro-display is $64\times36$ , with a $40\,\,\mu \text{m}\,\,\times 40\,\,\mu \text{m}$ pixel pitch. Starting from AlGaInP epi-layers grown on GaAs substrates, the monolithic red LED array was fabricated and

High-resolution and high-sensitivity optical vector analysis (OVA) is highly desired by many applications, such as optical sensors and photonic integrated circuits (PICs). However, it is difficult to achieve high resolution and high sensitivity simultaneously. Here, we propose and experimentally demonstrate a high sensitivity OVA using coherent detection to achieve the complex frequency responses (including

A versatile arbitrary bias control technology for Mach-Zehnder modulators (MZMs) based on a linear-frequency modulated (LFM) signal is proposed. An LFM signal is applied to the direct current (DC) port of an MZM together with a DC voltage. The output microwave signal is measured and cross-correlated with the fundamental and frequency-doubled components of the LFM signal. Their ratio serves as the feedback

In this letter, we present an optical fiber coupler for Fano resonance excitation of whispering gallery modes in microsphere resonators. The coupler can be fabricated conveniently by fusion-splicing an endface-etched fiber with a tapered fiber. Owing to the effective reflections from the fusion splicing-induced in-fiber bubble and the fiber taper tip, Fabry-Perot interference can be observed in the

In this letter, we experimentally demonstrate multi-band linear frequency modulation (LFM) signal generation subjected to multi-input optical injection in an external cavity-based Fabry-Pérot laser diode (ECFP-LD). The ECFP-LD is a specially designed FP-LD with a self-injected single longitudinal mode tuned up to 10 nm. The non-linear dynamics in period-one oscillation in ECFP-LD subjected to multi-input

Radio-over-fiber (RoF)-based front haul architecture has attracted considerable attention for fifth-generation (5G) cellular systems because of its cost effectiveness, however, it is susceptible to harmonic frequency distortion and intermodulation products (IMs) arising from the nonlinearity of the laser diode. To overcome this limitation, an asymmetric electrical predistortion method, using a single

Iterative demodulation and decoding has been introduced in 2005 by Colavolpe, Barbieri, and Caire to cope with channels affected by phase noise. However, iterations between the channel decoder and the demodulator increase system’s complexity. In this letter, we propose an iterative carrier recovery scheme where the current iteration is based on the hard decisions taken after the previous iteration

An integrated in-fiber coupling configuration for simultaneously exciting whispering gallery mode (WGM) and Fabry-Perot (FP) resonances in one cavity is proposed and demonstrated experimentally. The WGMs traveling circularly in both clockwise and counter-clockwise directions are simultaneously excited by perpendicularly injecting the light from the single-mode-fiber (SMF) core into a polymeric microsphere

We propose and experimentally demonstrate a novel design approach for scalable 3-port and 4-port mode insensitive multimode switching matrices for the first two quasi-transverse electric (TE) modes. The mode insensitive phase shifter ensures less power consumption for simultaneous multimode signal transmission in a mode division multiplexing (MDM) network. At 1550 nm, the 3-port switch exhibits approximately

We propose a fast circuit scheduling algorithm capable of supporting optical switch with microsecond-scale switching delays. By simultaneously calculating the max-weighted matching for all optical switches, this scheduling algorithm releases the linear dependence of the time complexity upon the number of optical switches. Further by replacing the recursion and pointer operations with sorting and iteration

The whispering gallery modes (WGMs) are studied theoretically in a proposed magneto-optic (MO) silicon micro-ring resonator with a radial magnetic field. The dispersion relations between both the frequency and polarization of the resonant mode and the gyration coefficient are achieved through Finite-Element Method (FEM). Nonreciprocal polarization coupling is observed between the intrinsic quasi-TM