Wavelength Division Demultiplexer Research Articles

Integrated 25 GHz and 50 GHz spectral line width dense wavelength division demultiplexer on single photonic crystal chip

We propose a new integrated demultiplexer model using the two-dimensional photonic crystal (2D PC) through the hexagonal resonant cavity (HRC) for the International Telecommunication Union (ITU) standard. The integrated model of demultiplexer for both 25 GHz and 50 GHz has been designed for the first time. The demultiplexer consists of bus input waveguide, drop waveguide, Hexagonal Resonant Cavity (HRC), 6 Air Hole Filter (6-AHF), 7 Air Hole Filter (7-AHF). The 7-AHF is used to filter 25GHz wavelength, and the 6-AHF filter is used to filter 50 GHz wavelength. The Q-factor on the designed demultiplexer is flexible based on the idea of increasing the number of air holes between drop waveguide and resonant cavity. The demultiplexer is designed to drop maximum 8 resonant wavelengths. One side of demultiplexer is able to drop 50 GHz ITU standard wavelengths, which are of 1556.3 nm, 1556.7 nm, 1557.1 nm and 1557.5 nm, and further the other facet is able to drop 25 GHz wavelengths, which are of 1551.4 nm, 1551.6 nm, 1551.8 nm, and 1552.0 nm. The proposed demultiplexer may be carried out within the integrated dual system. This system is able to lessen the architecture cost and the size is miniaturized substantially.

Wavelength-division demultiplexer based on hetero-structure octagonal-shape photonic crystal ring resonators

In this effort, a wavelength-division demultiplexer (WDM) is presented. The proposed device is formed by means of horizontal cascading of hetero-structure photonic crystal (PhC) ring resonators (RRs). In order to design this structure, four octagonal-shaped PhCRRs are horizontally connected. Each PhCRR creates a unique channel and has with a variable resonant wavelength. To achieve the required WDM channel spacing, every PhCRR is tuned to a unique resonant wavelength which is premeditated using various design parameters such as ring’s dielectric constant, surrounding medium’s dielectric constant, lattice dielectric constant, lattice constant in x or/and z direction and etc. Considering the ambient medium as air, rods dielectric constant as n = 3.6, and the PhC lattice with a = 558 nm in square type; the quality factor (Q) and drop efficiency of the base unit are found as 3100 and 100%, respectively, for operating at λ0 = 1550 nm. The simulation results are achieved by means of finite difference time domain (FDTD) method. These results show that the proposed WDM structure has a good performance in terms of average transmitted power higher than 95 ± 4%, reasonable channel spacing, low channel crosstalk (about -24db in worst case), and finally narrow full width half maximum (FWHM) bandwidth. The overall footprint of the proposed structure is calculated to be about ∼140 μm2, which makes this device a promising one for on-chip optical applications.

Multi-stage Mirror-Based Planar Structure for Wavelength Division Demultiplexing

Abstract In this paper, a new design for a demultiplexer device for Wavelength Division Multiplexing (WDM) communication system is proposed. The proposed device consists of an inhomogeneous layer of a semiconductor material with refractive index that is graded according to a given profile. To minimize the size of the proposed device and achieve better spatial shift between the multiplexed wavelengths, several mirrors are placed at different locations inside the device. These mirrors will force the multiplexed light to be reflected before reaching the total internal reflection point. By controlling the different design parameters such as incident angle, the refractive index profile, etc., a small size, low cost and less complexity WDM device can be realized. In the design process, we exploits the ray’s spatial shift that results from the introduced mirrors and the material dispersion. In addition, the effect of the aforementioned design parameters on the amount of spatial shift between the adjacent wavelengths and the size of the device has been investigated. Results show that the proposed design achieves higher spatial shift as well as smaller device size in comparison with precedent WDM device designs.

MMI-based all-optical four-channel wavelength division demultiplexer

In this paper, we present a four-channel wavelength division demultiplexer which is designed by means of cascading three $$1\times 2$$ multimode interference couplers. The proposed structure separates 980, 1310, 1490, and 1550 nm wavelengths into the appropriate ports. These wavelengths have been chosen for separation due to their importance in the optical communication systems. The performance of proposed demultiplexer has been optimized by choosing a suitable refractive index of the guiding region and geometrical parameters such as the width and length of coupler. Therefore, the total size of the demultiplexer is significantly reduced. Beam propagation method has been utilized in order to design and optimize the operation of the introduced structure. Simulation results indicate that the insertion losses of 980, 1310, 1490, and 1550 nm wavelengths are 0.52, 1.54, 0.64, and 1.4 dB, respectively.

Optical device terahertz integration in a two-dimensional-three-dimensional heterostructure.

The transmission properties of an off-planar integrated circuit including two wavelength division demultiplexers are designed, simulated, and analyzed in detail by the finite-difference time-domain method. The results show that the wavelength selection for different ports (0.404[c/a] at B2 port, 0.389[c/a] at B3 port, and 0.394[c/a] at B4 port) can be realized by adjusting the parameters. It is especially important that the off-planar integration between two complex devices is also realized. These simulated results give valuable promotions in the all-optical integrated circuit, especially in compact integration.

Wavelength division demultiplexing characteristics of photonic crystal square resonator

Wavelength division demultiplexing characteristics of photonic crystal square resonator

Frequency-dependent noise figure analysis of continuous photonic time-stretch system

In this paper, the frequency-dependent noise figure of a continuous photonic time-stretch system is theoretically analyzed and experimentally demonstrated. Mathematic analysis discloses that the frequency-dependent noise figure in the continuous photonic time-stretch system is mainly owing to the dispersion-induced phase shift in the link. In the experiment, a completely continuous signal is reconstructed with time-interleaved joining of four sections of time-stretched signals from optical wavelength-division de-multiplexing channels. The result of the frequency-dependent noise figure property agrees well with that of theoretical analysis.

Tunable all-optical switch/demultiplexer using nonlinear MMI waveguides

In this paper, a tunable optical switch/demultiplexer has been presented based on nonlinear multimode interference waveguides. The proposed structure can be utilized as a multi-wavelength optical switch or dynamic wavelength division demultiplexer. This dual application of the structure has been designed based on the cooperation of self-imaging and self-guiding phenomena of multimode waveguides. Simulation results show the mean value of insertion loss equal to −1.91 dB for the switching application of structure. Also, the wavelengths with 3 nm channel spacing and almost 3 nm full width at half power of outputs can be received in the multiplexing application. Two-dimensional beam propagation method has been utilized in order to simulate and verify the performance of proposed device.

Large-Scale Multilongitudinal Mode Fiber Laser Sensor Array With Wavelength/Frequency Division Multiplexing

A large-scale multilongitudinal mode fiber laser sensor array is proposed and demonstrated experimentally based on wavelength/frequency division multiplexing and beat frequency demodulation technique. In the proposed hybrid multiplexing sensing system, the frequency division multiplexing is realized by designing n fiber lasers with different cavity lengths, while the wavelength division multiplexing is achieved by incorporating a 1 × m coupler and an m -channel wavelength division demultiplexer. By making the operating wavelength of frequency-multiplexed lasers equal to the central wavelength of each channel in the demultiplexer, the light of each laser is coupled independently to the corresponding channel. Therefore, the multiplexing capability of the multilongitudinal mode fiber laser sensors is greatly improved and the maximum number of multiplexed sensors is m × n theoretically. To verify the proposed wavelength/frequency division multiplexing system, a 4 × 4 multilongitudinal mode fiber laser sensor array was set up and investigated. Experimental results show that there is a low crosstalk between the adjacent channels. The proposed wavelength/frequency hybrid multiplexing technology has the ability to monitor simultaneously a large number of fiber laser sensors.

Investigation on 2D photonic crystal-based eight-channel wavelength-division demultiplexer

In this paper, eight-channel wavelength-division demultiplexer (WDDM) is proposed and designed using two-dimensional photonic crystal (2DPC) ring resonator whose corresponding functional parameters such as transmission efficiency, resonant wavelength, Q factor are investigated. The proposed structure consists of bus waveguide, dropping waveguide and square ring resonators. Eight different channels are dropped by altering the cavity size and radius of the defect rods. The plane-wave expansion (PWE) and finite-difference time-domain (FDTD) methods are employed to analyse the photonic band gap (PBG) of periodic and non-periodic structure and to arrive normalized transmission spectra, respectively. The resonant wavelengths of eight-channel demultiplexers are 1496.9, 1502.3, 1506.9, 1512.3, 1515.0, 1520.4, 1525.3 and 1530.6 nm. The average transmission efficiency, Q factor and spectral width of proposed demultiplexer are 81%, 825 and 1.8 nm, respectively. The mean channel spacing is about 4.2 nm. The size of the demultiplexer is small; hence, it can be utilized for photonic integrated circuits (PIC).

Design and analysis of O–S–C triple band wavelength division demultiplexer using cascaded MMI couplers

Compact triple O–S–C band wavelength demultiplexer, which consists of series cascaded multimode interference (MMI) couplers has been carried out in this paper. The MMI coupler has been used to drop the wavelengths of 1510nm and 1550nm at bar port while the wavelength 1300nm into the cross port. Then another MMI coupler has been designed to separate the wavelength 1510nminto one port and wavelength 1550nm into another port. The triple wavelength demultiplexer function has been performed by choosing a suitable refractive index of the guiding region and geometrical parameters such as the width and length of MMI coupler. Numerical simulation with finite difference beam propagation method (BPM) has been utilized to design and optimize the operation of the proposed triple wavelength demultiplexer. The simulation results show that insertion losses of wavelength O, S and C, bands are 1.884dB, 1.452dB and 2.568dB, respectively, with isolations for each output waveguide ranging from 10dB to 28.72dB. The 3-dB bandwidth of insertion loss for 1300nm, 1510nm and 1550nm are 80nm, 20nm and 10nm, respectively.

Performance analysis of 2D-photonic crystal based eight channel wavelength division demultiplexer

This paper enumerates the design and performance analysis of eight channel Wavelength Division Demultiplexer (WDDM) using quasi square ring resonator based Two Dimensional Photonic Crystal (2DPC) lattice. The periodic array of inner rods in square shape, which is located inside the quasi square ring resonator whose dimension justifies resonant wavelength of the channels. The channels are dropped at output ports by altering the size of inner rods. The Plane Wave Expansion (PWE) and Finite Difference Time Domain (FDTD) methods are utilized to analyse the Photonic Band Gap (PBG) of periodic and non-periodic structure and to investigate the functional parameters of proposed demultiplexer. The functional parameters are resonant wavelengths, transmission efficiency, Q factor, spectral width, channel spacing and crosstalk. The obtained resonant wavelength of the eight channel demultiplexer is 1548.2nm, 1549.5nm, 1551.1nm, 1552.7nm, 1553.8nm, 1554.9nm, 1556.4nm and 1557.8nm. The average normalized transmission efficiency, Q factor, spectral width and channel spacing of proposed demultiplexer are 96%, 1922, 0.8nm and 1.4nm and lowest crosstalk is −26.9dB. The size of the device is small hence it can be applicable for Dense Wavelength Division Multiplexing in Photonic Integrated Circuits (PICs).

An optical demultiplexer based on photonic crystal ring resonators

A 4-channel wavelength division demultiplexer based on photonic crystal ring resonators suitable for WDM applications is proposed in this paper. For performing the demultiplexing task, we used four resonant rings with different geometrical parameters. A square lattice of two dimensional photonic crystal structure composed of dielectric rods was used as fundamental structure for designing the demultiplexer, which has two photonic band gap regions. The first band gap covers the optical communication wavelengths. For this demultiplexer, the minimum transmission efficiency is more than 92% and average channel spacing is 3.2nm.

Compact multichannel demultiplexer for WDM‐POF networks based on spatially overlapped FBGs

The fabrication of spatially overlapped fibre Bragg gratings over microstructured polymer optical fibre allows to demonstrate low-cost and compact multichannel wavelength division demultiplexers. Coarse and dense wavelengths in high-capacity optical systems have been demonstrated for reduced size environments with the advantages of polymer fibres.

Multi-channel terahertz wavelength division demultiplexer with defects-coupled photonic crystal waveguide

Terahertz (THz) wavelength division demultiplexer based on a compact defects-coupled photonic crystal waveguide is proposed and demonstrated numerically. This device consists of an input waveguide that perpendicularly coupled with a series of defects cavities, each of which captures the resonance frequency from the input waveguide. Coupled-mode theory and finite element method are used to analyze the transmission properties of the structure. It is found that the transmission wavelength centered around 1 THz can be adjusted by changing the geometrical parameters of defects cavities, which equals to THz waves generated by optical methods such as difference frequency generation and optical rectification. Applications in this frequency range are urgently needed. Furthermore, the highest transmission efficiency of 0.94 can be achieved when a perfect wavelength-selective mirror is set in the output waveguide.

Design of Polarization-Insensitive Demultiplexing Lattice Filters in SOI

In this paper, we propose a novel optimization technique that make use of nonlinear cost functions to design polarization-insensitive wavelength division demultiplexing (DEMUX) lattice filters in silicon-on-insulator (SOI) waveguides. These waveguides are characterized by large effective index and group index birefringences that are fully taken into account in the simulations. The optimization takes advantage of the periodicity of spectral responses of the various elements building a lattice filter. In performing the design, we consider design sensitivity to parameter variations and propose solutions that are compatible with CMOS processes using a waveguide thickness of 220 nm. The design can nonetheless be generalized to other waveguide dimensions and filter topologies for the realization of more complex integrated photonic circuits. Finally, we illustrate the approach by designing and simulating four channel demultiplexers with 200 and 800 GHz channel spacing in both the O- and C-band. Compared to the conventional polarization diversity scheme, this polarization-insensitive design methodology may reduce the total footprint and power consumption by up to 50%, and is therefore of great interest for short reach data communication applications.

Wavelength filtering and demultiplexing devices based on ultrathin corrugated MIM waveguides

We have numerically investigated the transmission properties of spoof surface plasmon polaritons on the ultrathin corrugated metal–insulator–metal (MIM) waveguides with different grooves. A band-pass plasmonic filter with T-shaped grooves and a compact 4-way wavelength division demultiplexing (WDM) incorporating the filter have been proposed. The whole 4-way WDM is more compact by the use of corrugated MIM waveguides with meander grooves. The near electric field distributions show that electromagnetic waves at different frequencies are guided and propagate along different branches with good isolation between branches. The experimental and numerical results have shown good agreements and validated the functions of the 4-way wavelength splitter. We also numerically investigate the 4-way WDM at terahertz frequencies by scaling down the whole structure. It is believed that the spoof plasmonic devices can find more applications in the plasmonic integration platform, such as optical communications, signal processing and spectral engineering.

Multi-user distribution of polarization entangled photon pairs

We experimentally demonstrate multi-user distribution of polarization entanglement using commercial telecom wavelength division demultiplexers. The entangled photon pairs are generated from a broadband source based on spontaneous parametric down conversion in a periodically poled lithium niobate crystal using a double path setup employing a Michelson interferometer and active phase stabilisation. We test and compare demultiplexers based on various technologies and analyze the effect of their characteristics, such as losses and polarization dependence, on the quality of the distributed entanglement for three channel pairs of each demultiplexer. In all cases, we obtain a Bell inequality violation, whose value depends on the demultiplexer features. This demonstrates that entanglement can be distributed to at least three user pairs of a network from a single source. Additionally, we verify for the best demultiplexer that the violation is maintained when the pairs are distributed over a total channel attenuation corresponding to 20 km of optical fiber. These techniques are therefore suitable for resource-efficient practical implementations of entanglement-based quantum key distribution and other quantum communication network applications.

Slow light enabled time and wavelength division demultiplexer in slotted photonic crystal waveguide

We have proposed a design for slow light with ultraflat dispersion in a slotted photonic crystal waveguide consisting of a hexagonal arrangement of elliptical air holes on a silicon-on-insulator substrate. The proposed structure has low group velocity and low group velocity dispersion with a wide normalized bandwidth range of 0.0089. The proposed structure can be used as an optical buffer for the storage of a large amount of data due to the large value of the normalized delay bandwidth product equal to 0.634. An optimized structure for a slotted photonic crystal has been analyzed for its applications as both a time and wavelength division demultiplexer. Furthermore, the time delay between two adjacent wavelengths (1550 and 1555 nm) is more than that reported earlier.

Optical filter and sensor based on plasmonic-gap-waveguide coupled with T-shaped resonators

A novel type of plasmonic filter consisting of metal–insulator–metal bus waveguides coupled with a T-shaped side-coupled cavities and stub waveguides. By finite-difference time-domain (FDTD) simulations, it is found that the resonant wavelength can be controlled by adjusting the length and height of the resonator. The effect of the asymmetry on the transmission property has also been examined. The result demonstrates that the asymmetrical plasmonic waveguide-resonator system performs a plasmonic analogue of electromagnetically induced transparency (EIT) in atomic systems, as confirmed by numerical experiments. The EIT-like transparency window exhibits a distinct resonance shift with respect to a small fluctuation in the refractive index of the surrounding medium, which can be used to increase the sensitivity of the plasmonic sensors. The proposed plasmonic filter and sensor have compact size that may find significant applications in highly-integrated dense wavelength division demultiplexing systems, nanoscale optical switching, and slow-light devices in highly integrated optical circuits and networks.