Optical Add-drop Filter Research Articles

Soliton spin manipulation using an optical add-drop filter

By using the optical add-drop filter which is formed by a microring resonator.After a dark soliton pulse is fed into an input port of the add-drop filter, the orthogonal soliton pair (dark and bright solitons) can be formed within the system and detected simultaneously at the output ports. Under the resonant condition, the conversion of dark and bright solitons corresponding to the left-hand and right hand soliton orientations can be generated and seen. Whenever a soliton(photon) is absorbed by an object, an angular momentum of either +h or −h is imparted to the object, in which two possible soliton states known as soliton spins are exhibited and confirmed by the helical phase presentation. In application, the train of orthogonal solitons, that is, many solitons (photons) with slightly different wavelengths can be generated by using the modified add-drop filter, which is available for many soliton spin investigations. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1100–1103, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26671

Optical spin generated by a soliton pulse in an add–drop filter for optoelectronic and spintronic use

A new concept of an optical spin generation using bright and dark soliton conversion behaviors within a modified optical add–drop filter known as PANDA ring resonator is proposed. The orthogonal solitons can be formed within the system and detected simultaneously at the output ports. Under the resonant condition, the dark and bright soliton pair corresponding to the left-hand and right-hand rotating solitons (photons) can be generated. When a soliton is absorbed by an object, an angular momentum of either +ħ or −ħ is imparted to the object, in which two possible spin states known as optoelectronic(soliton) spins are exhibited. Furthermore, an array of soliton spins, i.e. particles can be generated and detected by the proposed system, which can be used to form large scale spin generation.

Molecular Filter On-Chip Design

This paper presents the use of a modified add-drop optical filter known as a PANDA microing resonator which can be designed on a chip. By using an optical tweezer, the required molecules can be trapped and moved to the required destinations, where finally, the required molecules can be retrieved (filtered) by using the tunable filter via the add-drop filter control. In application, storage molecules in the bottle in the designed chip can be trapped and moved to the required targets by optical tweezers, which can transport via the optical waveguide. Therefore, this technique can be used to form the molecular filter. This is a new technique and important for drug delivery, drug targeting and molecular electronics, which is described, the optical tweezer generation using a PANDA ring resonator is also reviewed. Results obtained have shown that the multivariable filter can be obtained by tunable trapping control. the simulation results are obtained by using the commercial MATLAB software, which is found that this device can be used to form the hybrid electronic device, in which the combination between the conventional electronics and molecular electronics can be established, moreover, the multivariable molecular filter can be formed, which can be available for high capacity molecular communication and networks.

SOLITON SPIN AND WAVE-PARTICLE DUALITY

By using the optical add-drop filter which is formed by a microring resonator, and after a dark soliton pulse is fed into an input port of the add-drop filter, the orthogonal soliton pair (dark and bright solitons) can be formed within the system and detected simultaneously at the output ports. Under the resonant condition, the conversion of dark and bright solitons corresponding to the left-hand and right-hand soliton orientations can be generated and seen. Whenever a soliton (photon) is absorbed by an object, an angular momentum of either +ℏ or -ℏ is imparted to the object, in which two possible soliton states known as soliton spins are exhibited and confirmed by the helical phase presentation. In application, the train of orthogonal solitons, i.e. many solitons (photons) with slightly different wavelengths can be generated by using the modified add-drop filter, which is available for many soliton spins and long distance spin transport investigations.

Ultra-high quality factor planar Si_3N_4 ring resonators on Si substrates

We demonstrate planar Si3N4 ring resonators with ultra-high quality factors (Q) of 19 million, 28 million, and 7 million at 1060 nm, 1310 nm, and 1550 nm, respectively. By integrating the ultra-low-loss Si3N4 ring resonators with laterally offset planar waveguide directional couplers, optical add-drop and notch filters are demonstrated to have ultra-narrow bandwidths of 16 MHz, 38 MHz, and 300 MHz at 1060 nm, 1310 nm, and 1550 nm, respectively. These are the highest Qs reported for ring resonators with planar directional couplers, and ultra-narrowband microwave photonic filters can be realized based on these high-Q ring resonators.

Errata: Dark-soliton multiplexing system for high-capacity and -security communication within a wavelength router

We propose a novel system for generating multiplexed dark-soliton pulses using multiple light sources via an optical multiplexer, whereby dark solitons with different center wavelengths can be generated. The multiplexed signals can be transmitted into the communication link and filtered by using an optical add-drop filter. By using suitable simulation parameters, we have shown that dark solitons with different center wavelengths can in fact be obtained. In application, the communication capacity can be increased by using the multiplexed dark solitons; moreover, the transmission signals can be secured by utilizing the behavior of dark solitons. A free spectrum range (FSR) 2.5 nm and an amplified power of 30 W of dark solitons with wavelength 1.60 µm can be achieved. Channel spacing of the communication signals within a wavelength router can be provided by using a suitable FSR, which can be managed by using crosstalk effect analysis.

Integrated photonics devices on SU8 organic materials

In this paper, a gave a preview of targeted current research on integrated photonics based on the SU8 material was given. Such an approach takes advantage from a significant know-how regarding optical simulations by various analytical and numerical mathematical methods for the development of optical circuits on polymers. Original organic integrated photonics devoted to optical telecommunications and sensors applications on sundry waveguides structures, Mach-Zehnder interferometer (MZI), 2.5D and 3D Micro-resonators (MR), such as modulators, optical filters, devices for sensing pressure, gas and acid detections, heat flow measurements and future bio-detection schemes have been designed and realized last years. Present-day investigations deal with another main axis: The integration of 2.5D and 3D micro-resonator (MR) elements on photonic chips (optical add-drop filters circuits wavelength division de-multiplexing) which is under study, together with bio-sensors components based on the excitation of whispering gallery modes (WGMs) localized near the edge of the MR with sharp spectral resonance. Such issues and their solving approach highlight the interest to develop in the future specific hybrid processes such as biomolecular film deposition, self-assembled growth and handling, plasma treatments coupled with microtechnologic thin layers processes and micro-fluidic devices. Key words: Integrated photonics, waveguides structures, Mach-Zehnder interferometers, micro-resonators, organics materials.

Dark-soliton multiplexing system for high-capacity and -security communication within a wavelength router

We propose a novel system for generating multiplexed dark-soliton pulses using multiple light sources via an optical multiplexer, whereby dark solitons with different center wavelengths can be generated. The multiplexed signals can be transmitted into the communication link and filtered by using an optical add-drop filter. By using suitable simulation parameters, we have shown that dark solitons with different center wavelengths can in fact be obtained. In application, the communication capacity can be increased by using the multiplexed dark solitons; moreover, the transmission signals can be secured by utilizing the behavior of dark solitons. A free spectrum range (FSR) 2.5 nm and an amplified power of 30 W of dark solitons with wavelength 1.60 µm can be achieved. Channel spacing of the communication signals within a wavelength router can be provided by using a suitable FSR, which can be managed by using crosstalk effect analysis.

Synthesis of highly integrated optical network based on microdisk-resonator add-drop filters in silicon-on-insulator technology

We analyze a highly compact optical add-drop filter topology based on a pair of microdisk resonators and a bus waveguide intersection. The filter is further assessed on an integrated optical 4×4 network for optical on-chip communication. The proposed network structure, as compact as 50×50 µm, is fabricated in a CMOS-compatible process on a silicon-on-insulator (SOI) substrate. Finally, the experimental results demonstrate the proper operation of the fabricated devices.

DWDM self-healing access ring network with cost-saving, crosstalk-free and bidirectional OADM in single fiber

A cost-saving, crosstalk-free and bidirectional optical add-drop multiplexer (B-OADM) based on cascaded thin-film optical add-drop filters (TFOADFs) with optical circulators as well as the optical protection function promptly restored at the access node for a single-fiber self-healing access ring network are proposed and demonstrated. Using this B-TFOADM configuration, no crosstalk appears on the dropped and added channels, respectively. The bit-error rate performances in this B-OADM are investigated in a 2.5-Gb/s DWDM system, showing no intraband and interband crosstalk-induced power penalties. Such crosstalk-free and bidirectional architecture greatly simplifies the hub complexity as well as the low-cost components at each node are employed.

Silicon-on-Insulator Microring Add-Drop Filters With Free Spectral Ranges Over 30 nm

We demonstrate highly compact optical add-drop filters based on silicon-on-insulator microring resonators. The microring resonators have a small radius of 2.5 <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">mu</i> m and a very large free spectral range ~ 32 nm at the 1.55 <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">mu</i> m communication band. The propagation loss in such small micoring resonators was experimentally determined and shown to be extremely important in designing microring add-drop filters with low add-drop crosstalk, low drop loss, and maximally flat drop passband. For box-like channel dropping responses, second-order optical add-drop filters with two coupled microring resonators are designed and demonstrated, and the simulation matches well with the experiment. Devices were patterned with electron-beam lithography. Two fabrication procedures utilizing different polarity of resists were introduced and compared, and the process with negative resist resulted in much smaller sidewall roughness of waveguides, thus reducing the propagation loss in microring resonators.

Reconfigurable Add–Drop Optical Filter Based on Arrays of Digital Micromirrors

We demonstrate a universal reconfigurable add-drop optical filter based on arrays of digital micromirrors. Our approach allows for reconfiguration of the device parameters for operation in different sets of channel wavelengths, even or uneven channel-to-channel separation, adjustable channel passband, and dynamic add-drop of optical signals. The proposed device shows insertion loss at the center wavelength in the all-pass configuration of 7.6 dB, extinction ratio of 35 dB, channel isolation better than 24dB, negligible loss ripple, and possibility of reconfiguration time in the order of microseconds. Although designed for demonstration on optical telecommunication frequencies, the high-flexibility features of the proposed add-drop filter allow it to be used for other optical wavelength-based filtering/switching applications.

Symmetry analysis and numerical simulation of mode characteristics for equilateral-polygonal optical microresonators

Mode characteristics for two-dimensional equilateral-polygonal microresonators are investigated based on symmetry analysis and finite-difference time-domain numerical simulation. The symmetries of the resonators can be described by the point group ${C}_{Nv}$, accordingly, the confined modes in these resonators can be classified into irreducible representations of the point group ${C}_{Nv}$. Compared with circular resonators, the modes in equilateral-polygonal resonators have different characteristics due to the break of symmetries, such as the split of double-degenerate modes, high field intensity in the center region, and anomalous traveling-wave modes, which should be considered in the designs of the polygonal resonator microlasers or optical add-drop filters.

Optical add-drop filters based on photonic crystal ring resonators

We present here an optical add-drop filter (ADF) design based on ultra-compact photonic crystal ring resonators (PCRRs). The normalized transmission spectra for single-ring and dual-ring configurations have been investigated by using the two-dimensional finite-difference time-domain (FDTD) technique in a square lattice dielectric-rod photonic-crystal structure. With the introduction of four scatterers at the corners of quasisquare- ring PCRR, high wavelength selectivity and close to 100% drop efficiency can be obtained. Both backward- and forward-dropping were achieved by controlling the coupling efficiency between two PCRR rings for resonant modes with different symmetry. The resonant-mode quality factor Q and the wavelength tunability were also analyzed, opening opportunities for PCRRs as ultra-compact filters, optical add-drop multiplexers, electrooptical N x N switches and electrooptical modulators.

Comparative study of the integration density for passive linear planar light-wave circuits based on three different kinds of nanophotonic waveguide

A theoretical analysis and comparison of the integration density are given for passive planar lightwave circuits based on three different kinds of nanophotonic waveguide, namely, photonic crystal waveguides, Si nanowire waveguides, and nanoslot waveguides. Two criteria for determining the integration density are used. One is the minimal decoupled separation between two parallel nanophotonic waveguides, and the other is the area occupied by a low-loss 90 degree turn. Some important functional components (such as Y branches and optical add-drop filters) are also chosen as basic elements to evaluate the integration density. It is shown that the integration densities of passive linear planar lightwave circuits based on these three kinds of nanophotonic waveguide are comparable.

Demonstration of the MEMS Digital Micromirror Device-Based Broadband Reconfigurable Optical Add–Drop Filter for Dense Wavelength-Division-Multiplexing Systems

For the first time, an optimized optical add-drop filter (OADF) for dense wavelength-division-multiplexing systems is demonstrated using the Texas Instruments microelectro-mechanical-system Digital Micromirror Device (DMDtrade). This OADF features a polarization-insensitive fault-tolerant broadband operation, low loss, and the ability to selectively add/drop with high-wavelength-resolution multiple channels in the C telecommunications band. The proof-of-concept OADF designed for the C-band demonstrates low insertion loss, 0.15-dB polarization dependent loss, 3-dB wavelength resolution of 0.4 nm, and an average crosstalk of better than 30 dB. With the use of a reference mirror, the OADF becomes a multiwavelength 2 times 2 routing switch

Design, simulation, and characterization of a passive optical add-drop filter in silicon-on-insulator technology

We present a passive novel optical add-drop filter incorporating microdisk resonators, in complementary metal-oxide-semiconductor compatible silicon-on-insulator technology, which enables a simple layout of complex optical networks-on-chip. The measured properties of the fabricated devices are in agreement with theory, established using the time-domain coupled mode theory and finite-difference time-domain simulations.

Long-period-grating-assisted optical add-drop filter based on mismatched twin-core photosensitive-cladding fiber.

A noninterferometric optical fiber add-drop channel filter based on a mismatched twin-core photosensitive-cladding fiber and long-period fiber grating is demonstrated. With assistance from the fiber grating, co-directional spectrally selective cross coupling between the two cores can be realized with an efficiency of 90%.

Photonics Filters, Switches and Subsystems for Next-generation Optical Networks

This article reviews a host of photonics devices and subsystems research that are of increasing interest for next-generation wavelength division multiplexing optical networks. On the device front, we report our initial results on silicon-based planar optical micro-resonator channel add-drop filters, and on liquid-crystal-based optical switches and tunable devices. On the subsystem work, we report an effective and scalable protection switching for large-capacity MEMS-based optical crossconnect systems.

Fixed low-channel-count optical add-drop multiplexer filter concatenation experiments with 50-GHz channel spacing and 10-Gbit/s NRZ signals

Experimental results are presented for the first time of Q penalties resulting from multiple passes through commonly available fixed optical add-drop multiplexers (OADMs) in a 50-GHz channel plan at 10 Gbit/s. We find that transmission through >6 OADMs is feasible within a laser center frequency range of ±2.5 GHz with a Q penalty of <1 dB. We find expressions for the Q penalty contributions from distortion-induced eye closure and optical signal-to-noise ratio (OSNR) degradation and show that the predicted penalty functions from these components fit very well the measured Q penalty as a function of laser-frequency offset within a filter passband. Both contributions are necessary for accurately predicting the total Q penalty.