Optical Communication Region Research Articles

A Submicrosecond-Response Ultraviolet-Visible-Near-Infrared Broadband Photodetector Based on 2D Tellurosilicate InSiTe3.

2D material (2DM) based photodetectors with broadband photoresponse are of great value for a vast number of applications such as multiwavelength photodetection, imaging, and night vision. However, compared with traditional photodetectors based on bulk material, the relatively slow speed performance of 2DM based photodetectors hinders their practical applications. Herein, a submicrosecond-response photodetector based on ternary telluride InSiTe3 with trigonal symmetry and layered structure was demonstrated in this study. The InSiTe3 based photodetectors exhibit an ultrafast photoresponse (545-576 ns) and broadband detection capabilities from the ultraviolet (UV) to the near-infrared (NIR) optical communication region (365-1310 nm). Besides, the photodetector presents an outstanding reversible and stable photoresponse in which the response performance remains consistent within 200 000 cycles of switch operation. These significant findings suggest that InSiTe3 can be a promising candidate for constructing fast response broadband 2DM based optoelectronic devices.

Continuously and reversibly electro-tunable optical nanoantennas based on phase transition of vanadium dioxide

Optical nanoantennas have attracted significant attention over the past decades, owing to their exceptional capabilities in terms of light manipulation and versatile optical applications. Recently, active nanoantennas have been developed by introducing phase change materials, to achieve specific tunable electromagnetic responses. However, most of these attempts only function with ‘ON’/‘OFF’ states or switch in a few discrete states, significantly restricting the application in dynamic tunability. Thus far, the continuous and reversible modulation of optical nanoantennas has not been sufficiently explored. In this article, we experimentally demonstrate a continuously and reversibly electro-tunable optical nanoantenna, by integrating an asymmetric gold nanodisk dimer array with a vanadium dioxide (VO2) film and graphene thin film. By accurately controlling the applied electrical current, the Joule heat generated in the graphene film excites the metal-insulator phase transition of VO2, and the refractive index of VO2 exhibits a relatively large variation. When VO2 is in the insulating phase, we observe an apparent resonance dip in the reflection spectrum, which is attributed to a hybrid mode originating from the gap plasmon in the dimers and localized surface plasmon (LSP) resonance excited at the edge of the nanodisks. Meanwhile, owing to the coupling between two asymmetric LSP resonances in the neighboring nanodisks, the reflected peak based on the Fano effect is realized. However, once VO2 is in the metallic phase, the hybrid mode becomes weaker and red-shifted, and the Fano effect disappears. Thereafter, the continuous and reversible electro-modulation of the nanoantenna features, including the resonant wavelength, resonant intensity, and quality factors (Q), are experimentally verified in the optical communication region, by varying the applied electrical current in the hybrid structure. To further increase the modulation range of these properties, we scan the gap size and structural asymmetry parameter of the nanodisk dimer. The results show that, with a smaller gap size, the resonant intensity of the nanoantenna is stronger. When the structural asymmetry parameter increases, the resonant wavelength is redshifted. We expect that such continuously and reversibly electro-tunable nanoantennas will stimulate various applications in optical communication systems, tunable photoelectric sensors, and beyond.

C60 nanorods as a promising infrared nonlinear optical material for ultrafast photonics

As a typical one dimensional (1D) crystals, C60 nanorods has attracted widely attention in ultrafast optical field due to its excellent photoelectric properties, including broadened and extended optical absorption, high photosensitivity as well as photogenerated charge carriers mobility. Here, C60 nanorods are synthesized by a liquid-liquid interfacial precipitation method of m-xylene and isopropyl alcohol (IPA) solution. By tuning the solvent amount ratio, a hexagonal close-packed polycrystalline nanorod structure with a broadband absorbance spectrum is achieved. Its’ nonlinear optical absorption characteristics are studied through a balanced twin-detector measurement system. Experimental results show that C60 nanorods has excellent nonlinear absorption with a high modulation depth of ∼16% and a low nonsaturable absorption of ∼4%. Besides, a high optical-to-optical slope efficiency of 7.8% mode-locking all fiber laser is achieved in the optical communication region. The C60 nanorods has great prospect on high effective fiber laser mode locking and open a new way for the development of ultrafast optical devices.

The influence of relative refractive index and core diameter on properties of single-mode optical fiber.

A study of the influence of the parameters design, such as the refractive index of the core, the cladding and the radius of the core on propagation constant (β) of single-mode optical fiber in optical communication region (1.2-1.6) m have been investigated. Material, waveguide, and profile dispersions are analyzed and investigated. Three models of optical fibers with different relative refractive indices () (0.004, 0.007, 0.01) at a wavelength equal 1.55 m, and three models of core radius (3,4,5) m is taken in the count. Numerical simulations and modeling are arranged depending on weakly guiding approximation for solving homogeneous wave equation derived from Maxwell’s equations. Our modeling solved by the aid of MATLAB software. Material and profile dispersion have no significant change for various relative refractive index, while waveguide dispersion is affected by the change of relative refractive index. the waveguide dispersion increased by increasing core diameter and the profile dispersion decreased as the core diameter increased. There is no effect on martial dispersion by increasing the core diameter.

Sb4O5Cl2 for 34th-order-harmonic mode locking

Due to the excellent electrochemical characteristics, Sb4O5Cl2 has been potentially used in flame retardant, catalyst, and anode materials, etc. At the same time, it has broad application prospects in optics and optoelectronics because of its strong inoxidizability, high damage threshold and relatively high-photoelectric conversion efficiency. However, the application of Sb4O5Cl2 in ultra-fast photonics has not been reported so far. In this work, the structure characteristic and nonlinear optics property of Sb4O5Cl2 have been systematically studied. The result indicates saturation intensity and modulation depth are 402.5 MW/cm2 and 1.3%, which prove Sb4O5Cl2 could be utilized as a saturable absorber (SA) in ultrafast photonics. Especially, harmonic mode-locking with 850-fs pulse duration, 2.86-nm 3-dB bandwidth, 202.3-MHz maximum repetition rate in optical communication region is generated based on a tapered fiber incorporated with Sb4O5Cl2 for the first time to our knowledge. This work opens novel avenues toward optoelectronics device based on Sb4O5Cl2 in the fields of optical modulation, optical detection and optical communication, etc.

Ultrafast photonics application of graphdiyne in the optical communication region

As a kind of novel allotrope of carbon, graphdiyne (GDY) has attracted wide interest of scientists from different fields. Due to excellent electrical and optical properties, it has important and promising prospects in the fields of energy, catalysis and optoelectronics, etc. However, investigations of this emerging material on nonlinear optics and ultrafast photonics are rarely involved. In our work, we have fabricated a saturable absorber (SA) based on graphdiyne and applied it to an erbium-doped fiber laser at the 1.5 μm region. Based on the evanescent field interaction, we obtain the mode-locked laser pulse at a center wavelength of 1564.70 nm which has a repetition rate of 12.05 MHz and a pulse width of 734 fs. This is the first time that graphdiyne has been used as a SA to obtain a mode-locked fiber laser in femtosecond level, which proves the great prospect of graphdiyne on fiber lasers and opens up a path for its application in ultrafast photonics and optoelectronics.

Ultra-fast photodetectors based on high-mobility indium gallium antimonide nanowires

Because of tunable bandgap and high carrier mobility, ternary III-V nanowires (NWs) have demonstrated enormous potential for advanced applications. However, the synthesis of large-scale and highly-crystalline InxGa1−xSb NWs is still a challenge. Here, we achieve high-density and crystalline stoichiometric InxGa1−xSb (0.09 < x < 0.28) NWs on amorphous substrates with the uniform phase-purity and <110 >-orientation via chemical vapor deposition. The as-prepared NWs show excellent electrical and optoelectronic characteristics, including the high hole mobility (i.e. 463 cm2 V−1 s−1 for In0.09Ga0.91Sb NWs) as well as broadband and ultrafast photoresponse over the visible and infrared optical communication region (1550 nm). Specifically, the In0.28Ga0.72Sb NW device yields efficient rise and decay times down to 38 and 53 μs, respectively, along with the responsivity of 6000 A W−1 and external quantum efficiency of 4.8 × 106 % towards 1550 nm regime. High-performance NW parallel-arrayed devices can also be fabricated to illustrate their large-scale device integrability for next-generation, ultrafast, high-responsivity and broadband photodetectors.

Tunable ultra-narrowband and wide-angle graphene-based perfect absorber in the optical communication region

A tunable ultra-narrowband and wide-angle graphene-based perfect absorber, in which monolayer graphene is on top of the dielectric metasurface backed by a silver substrate, is proposed. Through finite-difference time-domain (FDTD) simulations, an ultra-narrowband perfect absorption peak with a 3 dB bandwidth of 0.5 nm, which is a remarkable value compared with the previous results, is realized in the optical communication region. Moreover, the absorption amplitude can be efficiently modulated by varying the Fermi energy of graphene. Furthermore, the proposed absorber can tolerate a wide range of incident angles and demonstrates a dependence on polarization.

Synthesis and Optoelectronic Performance of III-V Nanowires

III-V semiconductor nanowires (NWs), such as InAs, GaAs, InP, are promising materials for applications in infrared optoelectronic devices because of their typically high carrier mobilities and narrow band gap. In view of expanding the application fields, a major opportunity for III-V NWs and their applications lies in the tunability of bandgaps. Here, the complete composition range InAsxP1-x alloy NWs with potential bandgap tunability from the near-IR region to the mid-IR region were synthesized by a new route combining the vapor-liquid-solid (VLS) growth mechanism with an additional ion-exchange (IE) process. Based on these as-grown InAsxP1-x NWs, broadly band tunable nanometer-scale infrared photodetectors (PDs) have been achieved. In addition, high quality GaSb/GaInSb p–n heterojunction semiconductor nanowires were synthesized successfully via a simple chemical vapor deposition (CVD) method. Based on these nanowires, high-performance photodetectors were constructed with an external quantum efficiency of 104, a responsivity of 103 A/W, and a short response time of 2 ms in the infrared optical communication region (1.55 μm). These III-V NWs shows promising potential applications in integrated photonics and optoelectronics devices or systems. ­­­­­­­­­­­­­­­­­­

Emission characteristics of self-assembled strained Ge1−xSnx islands for sources in the optical communication region

Self-assembled strained Ge1−xSnx islands on Si (100) have been grown at a low temperature using molecular beam epitaxy. The in-built strain and fraction of Sn in the islands have been estimated using x-ray photoelectron spectroscopy and high resolution x-ray diffraction study of grown samples. No-phonon assisted transition in the optical communication wavelength range of 1.4–1.8 μm has been observed in the Ge1−xSnx island samples. The direct band gap transition intensity is found to increase with a growth in Sn concentration, with this increase in intensity sustained up to a temperature of 130 K in Ge1−xSnx islands. The observed electroluminescence in p-i-n devices fabricated on Ge1−xSnx island samples above a threshold bias of 4 V makes them attractive for future Si based optical devices.

Bandgap-engineered GaAsSb alloy nanowires for near-infrared photodetection at 1.31 μm

Single-nanowire photodetectors have potential applications in integrated optoelectronic devices and systems. Here, bandgap-engineered GaAs0.26Sb0.74 alloy nanowires were synthesized via a chemical vapor deposition method. The synthesized nanowires are single crystals grown along the [111]B direction with length up to 50 μm and diameter ranging from 40 to 500 nm. Photodetectors are built based on these single-alloy nanowires, which show a wide response in the near-infrared region with a high response peak located in the optical communication region (1.31 μm), as well as an external quantum efficiency of 1.62 × 105%, a responsivity of 1.7 × 103 A W−1 and a short response time of 60 ms. These novel near-infrared photodetectors may find promising potential applications in integrated infrared photodetection, thermal imaging, information communication and processing.

Preparation and Characterization of Thermally Stable Silicon-Containing Fluoropolymer Matrix for Application to Erbium-Doped Waveguide Amplifiers

This study focuses on the fabrication of fluoropolymer films as erbium(Er3+) host material with a goal of achieving sufficient thermal stability, optical clarity in the optical communication region and a chemical resistance to withstand typical fabrication processing and operation conditions. To satisfy the demands mentioned above, acrylo-polyhedral oligomeric silsesquioxane as heat-resistance improver, 2,2,3,3,4,4,5,5-octafluoropentyl acrylate as fluorinated acrylic monomer, tetrahydrofurfuryl acrylate as solubility enhancer, 3-(trimethoxysilyl)propyl methacrylate as both a silane coupling agent and another heat-resistance improver and Darocur 4265 as photoinitiator were used. Various compositions were evaluated to obtain high quantity of Er3+ ions in the polymer matrix, high thermal stability and high transparency.

Room-Temperature Near-Infrared Photodetectors Based on Single Heterojunction Nanowires

Nanoscale near-infrared photodetectors are attractive for their potential applications in integrated optoelectronic devices. Here we report the synthesis of GaSb/GaInSb p-n heterojunction semiconductor nanowires for the first time through a controllable chemical vapor deposition (CVD) route. Based on these nanowires, room-temperature, high-performance, near-infrared photodetectors were constructed. The fabricated devices show excellent light response in the infrared optical communication region (1.55 μm), with an external quantum efficiency of 10(4), a responsivity of 10(3) A/W, and a short response time of 2 ms, which shows promising potential applications in integrated photonics and optoelectronics devices or systems.

Epitaxial AlGaAsSbGaSb (AlGaSb) heterostructures for injection lasers

AbstractA possibility is shown of obtaining nearly perfect heterojunctions in the GaAlAsSb—GaAlSb system which do not contain any remarkable density of lattice mismatch defects at the heteroboundaries. Application to low threshold DH injection lasers for 1.4–1.8 μm spectral region for optical communications, moist‐o‐graphs etc.