Top PDF Photonic crystal Bragg lasers : design, fabrication, and characterization

Photonic crystal Bragg lasers : design, fabrication, and characterization

Photonic crystal Bragg lasers : design, fabrication, and characterization

I would like to thank everyone in our group. I am fortunate to have them as my labmates and have learned a lot from them. Especially, I want to thank Professor Joyce Poon, who helped me solve a lot of research problems in my project, and Dr. Will Green, who gave me the first lesson in fabrication and trained me in this field. I would like to express my appreciation to the post-docs and visiting scholars for their discussions and support: Dr. Philip Chak, T. R. Chen, Professor Yanyi Huang, Dr. Reg Lee, Professor Koby Scheuer, and Professor Yong Xu. Yangyi introduced me to the world of the optical experiment, while Philip showed me the deep understanding and precise thinking of the theory. I would like to thank all the students that I have worked with over the years: Dr. John Choi, Ali Ghaffari, Hsi-Chun Liu, Dr. Wei Liang, Dr. George Paloczi, James Raftery, Naresh Satyan, Christos Santis, Jacob Sendowski, and Xiankai Sun. John and Xiankai helped me a lot with the laser measurement setup and packaging. Also, I would like to acknowledge the staff in our group: Kevin Cooper, Irene Loera, and Connie Rodriguez.
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Design, fabrication and Optical Characterization of Multi Component Photonic Crystals for Integrated Si Microphotonics

Design, fabrication and Optical Characterization of Multi Component Photonic Crystals for Integrated Si Microphotonics

Let us use the suggested in the previous section maps of TBs for the fabrication of the real band-pass optical filter with wide bandwidth operating in a mid-infrared (MIR) wavelength range. In order to introduce the third component into original two-component structure, we exploited thermal oxidation of the grooved Si structures. While other complex and more expensive deposition techniques, such as chemical vapour deposition or sputtering, can be used to deposit dielectric layers, thermal oxidation of Si has the advantage of having a better growth isotropy, especially for narrow, deep trenches and precise control of the grown thickness. Also the fundamental limitations of fabricated Si based devices, such as high roughness and corrugation of the etched Si surfaces, can be overcomed by oxidation smoothing. In the course of the model calculations we have to pay attention to the following important issues. Firstly, owing to the strong absorption band of Si0 2 around 9 μm in MIR range of spectra, the imaginary part of Si0 2 refractive index, n SiO2 , has been taken into
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Design, Fabrication, and Characterization of 3D Nanolattice Photonic Crystals for Bandgap and Refractive Index Engineering

Design, Fabrication, and Characterization of 3D Nanolattice Photonic Crystals for Bandgap and Refractive Index Engineering

We utilize the commercially available TPL DLW system produced by Nanoscribe GmbH in our fabrication process. The TPL DLW workflow first involves designing the desired 3D architecture using a computer aided design (CAD) program like SolidWorks (Figure 1(a)), after which the design is imported to NanoWrite, a proprietary software program that interfaces with the Nanoscribe TPL instrument (Figure 1(b)). Once the structure is defined, a 780nm femtosecond pulsed laser is focused down to a voxel within a droplet of liquid photo-sensitive monomer. Throughout this thesis, the photoresist used is commercially known as IP-Dip (Nanocribe GmbH), and is composed of the monomer pentaerythritol triacrylate (PETA) and the photoinitiator 7-diethylamino-3-thenoylcoumarin (DETC). Within the voxel volume, simultaneous two-photon absorption is possible, leading to the excitation of DETC radicals which initialize polymerization of the PETA monomer. As PETA is a multi-functional monomer, i.e., a monomer with more than one acrylate groups, a cross-linked polymer network is created that is insoluble. The voxel is elliptically shaped and is traced in 3-dimensions within the photoresist droplet, creating a polymer structure of any arbitrary geometry (Figure 1(c)). Laser power and speed can also be modulated, which will impact voxel size, resulting in the creation of features with transverse dimensions as small as 150 nm. 31
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Design, fabrication and optical characterization of one dimensional two  and multi component photonic crystals based on silicon

Design, fabrication and optical characterization of one dimensional two and multi component photonic crystals based on silicon

Section 4.4.5 Optimization: Compensation of the fabrication tolerances Number of periods, N Lattice constant, a fpm Filling fraction of Si fsi Refractive index of Si, nH=nsi Refractive i[r]

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Design, fabrication, and characterization of semiconductor transverse Bragg resonance lasers

Design, fabrication, and characterization of semiconductor transverse Bragg resonance lasers

Eq. 5.34 gives the largest allowed propagation constant to isolate a TBR mode, it must be combined with Eq. 4.7 which gives the smallest allowed propapagation constant for coupling light out at a facet oriented normal to the grating momenutum vector (k = π/Λ). Another consequence is that the index guided modes below the light line will always have low loss compared to the TBR modes due to the very property that creates the advantage of loss dependence. This means that these index guided modes must be suppressed through control of the longitudinal propagation constant, necessitating the use of longitudinal mode control in addition to the transverse mode control provided by the Bragg cladding.
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Design and Characterization of Low-Loss Porous-Core Photonic Crystal Fiber

Design and Characterization of Low-Loss Porous-Core Photonic Crystal Fiber

A novel design incorporating both a porous core and also a porous clad has been presented here, this being a better design than a PCF with porous cladding [19], [20] or a porous-core [32], [33] fiber with air cladding. In this paper, a rigorous full-vectorial modal solution approach has been used to optimize the index contrast and the dimensions to maximize the power confinement in the air holes. It has been shown here that, by using a porous core along with the porous cladding of a conventional PCF, the power confinement in the air holes can be significantly increased, which will reduce the effect of material loss by 60% for the solid Teflon. The overall loss value can be further reduced if the material loss can be reduced or the fabrication technology improved to allow a higher d= value than 0.95 (for the outer d =), which is considered in this paper. It has been shown that the leakage loss and the bending losses for such a PCF are very small for practical applications. The manufacturing technology for PCF operating at optical frequencies has matured, and PCFs with a submicron pitch are routinely being fabricated. Compared with that, PCF for THz frequencies with a pitch 100 times larger would be relatively easy to fabricate, and such a PCF has also been fabricated [19], [20]. In the design reported here, when a THz PCF with additionally porous core [33] is considered, the 20- to 40-m inner pitch dimensions are easily feasible, and the fabrication process does not introduce any additional challenge. The design shown here, with a fixed o = i
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Photonic waveguide engineering using pulsed lasers – A novel approach for non-clean room fabrication!

Photonic waveguide engineering using pulsed lasers – A novel approach for non-clean room fabrication!

Optical polymers such as PDMS depict worse rare-earth ion solubility characteristics than silica and silicate inorganic glass hosts, consequently and it is impossible to design efficient Er 3+ -doped polymer waveguides for engineering lossless splitters, which can then potentially open the opportunity for engineering seamless and complex photon carrier circuits for the backplane of PCs. In an earlier approach [7], investigations into whether the deposition of a large expansion coefficient glass on a PDMS substrate might be feasible for engineering a suitable gain medium. However it was soon realized that the apparent large mismatch between the coefficients of thermal expansion and elastic constants of an Er 3+ - phosphate modified tellurite glass and PDMS were the two main barriers for film growth. It is for this reason a nano-scale glass-polymer superlattice approach was proposed using excimer PLD [4,6], in which a multilayer structure of these two dissimilar materials were sequentially deposited to grow 100s of nanometer thick layers for waveguide engineering. An exemplar microstructure of PDMS-glass superlattice, grown using sequential deposition of these two materials is shown in Fig. 4, which was characterized for spectroscopic properties, including the lifetime of 1-2 ms in the film and waveguide structures. Note that although the PDMS is possible to process using standard cleanroom techniques, the nano- composite materials are impossible to etch or selectively ion-beam mill. For this reason, the 100fs pulsed laser was used for waveguide inscription and fluorescence characterization [7]. Preliminary data from waveguide engineering is sufficiently encouraging to advance this technique of sequential deposition to the next level for gain characterization in future.
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Design and Characterization of Porous Core Polarization Maintaining Photonic Crystal Fiber for THz Guidance

Design and Characterization of Porous Core Polarization Maintaining Photonic Crystal Fiber for THz Guidance

d is decreased, effective index increases for both the TE and TM polarizations and the modal index difference between the two fundamental quasi-TE and quasi-TM increases, shown by a blue dotted line with stars. Changing of d 2 makes the PCF structure more asymmetric and it is shown here that birefringence value as large as 0.012 can be easily achieved and this structure can also be easily produced by using simpler stack-and-draw approaches. Although higher birefringence value of 0.026 has been reported earlier [40] but they would require a more complex fabrication process, possibly using the extrusion process.
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Characterization of Defect Modes in Onedimensional Ternary Metallo-Dielectric Nanolayered Photonic Crystal

Characterization of Defect Modes in Onedimensional Ternary Metallo-Dielectric Nanolayered Photonic Crystal

binary, ternary and so on. Binary PC includes two layers in each period; ternary PC contains three layers in each period and so on. Finally, these periods are repeated several times to form PCs [5]. 1D PCs can be dielectric with negative index of refraction in which optical properties change in one direction, while in two other directions, the structure is uniform [6]. The simplest PC is unidimensional and corresponds to a Bragg reflector. A two-dimensional PC can be a set of parallel identical cylinders (dielectric or metallic rods in a dielectric material) periodically arranged in homogeneous medium. A three-dimensional crystal can be, for instance, a set of identical spheres periodically arranged. But many other patterns have also been tested [7]. A one-dimensional ternary symmetric metallo-dielectric photonic crystal (1DTSMDPC) is a periodic structure consisting of dielectric and metal elements with different refractive indices. There are some advantages in using metals in PCs such as decreased size, simpler fabrication, and lower costs. 1DTSMDPC has wider band gaps as compared with one-dimensional binary symmetric metallo-dielectric photonic crystal (1DBSMDPC) and the speed of enhancement of defect modes with increasing thickness and index of refraction of dielectric defect layer in 1DTSMDPC is more than 1DBSMDPC. Because 1D PCs have easy fabrication, they have many applications such as multilayer’s coatings [8], Bragg reflectors [9], narrow band filters [10], and fibers [11]. Besides, there are a lot of researches in using metals in recent years [12–16]. Photonic band gap (PBG) is in the ranges of frequency in which light cannot propagate through the PC. Moreover, if we enter a disorder into the regular dielectric structure of the PC, we will obtain mid gap modes whose eigenfunctions are localized around the disorder. These modes are called localized defect modes [1].
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Design and Characterization Study of Endless Single Mode (ESM) Photonic Crystal Fiber Using Finite Element Method

Design and Characterization Study of Endless Single Mode (ESM) Photonic Crystal Fiber Using Finite Element Method

Photonic Crystal Fibers (PCFs), also called holey fibers or microstructured optical fibers in some literatures, are considered as a revolution in optical fiber technology. These fibers are essentially low-loss waveguides which consist of a core surrounded by a periodic array of air holes in the cladding region. This configuration has led to a number of novel properties like Endless Single Mode (ESM) operation, controllable dispersion characteristics and a high degree of nonlinearity [1]. Due to these properties, it has potential applications in high power fiber lasers, fiber amplifiers, non- linear devices, optical sensors, fiber-optic communication and many others [2]. The cladding of a PCF can be constructed with a structure similar to that found in photonic crystal. This is where the term ‘photonic crystal fiber’ originates. Photonic crystals are essentially a photonic analog of the electronic crystal. They are periodic structures on the scale of optical wavelength (much larger than the atomic size of electronic wavelengths) [3]. There are two classes of PCFs : Solid Core PCF (SC-PCF) and Hollow-Core PCF (HC-PCF). The term SC-PCF refers to those structures that have a solid core which is usually made of silica. These fibers guide light by the phenomenon of total internal reflection. On the other hand, HC-PCF has an air hole in the core region and transmits light by photonic bandgap type guidance [4].
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The Optical Properties of Bragg Fiber with a Fiber Core of 2-Dimension Elliptical-Hole Photonic Crystal Structure

The Optical Properties of Bragg Fiber with a Fiber Core of 2-Dimension Elliptical-Hole Photonic Crystal Structure

Photonic crystal fibers (PCFs) [1–4] which also include Bragg fibers [5–8] have attracted increasing interest over the past decade because of their unique property, such as high birefringence, high nonlinearity, endless single-mode operation, single-polarization single- mode operation, and tailorable chromatic dispersion. Highly birefringent PCFs are one kind of extremely important PCFs which have promising applications in e.g., fiber sensors [9], fiber lasers [10, 11], and fiber filters [12]. So far, various highly birefringent PCFs have been proposed [13–17]. Meanwhile, Bragg fibers have recently received much attention for their interesting dispersion and modal properties and for advances in fabrication techniques [18]. However, so far there is no report about birefringent Bragg fibers. As the birefringent Bragg fiber is based on band gap effect; it will be more suitable for bending operation with lower loss. Thus, a combination of Bragg fiber with birefringence is a good trying for the design of novel fibers.
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Design And Evaluation Of Distributed Bragg Reflector From 1d Photonic Crystal Using Zemax And Teraplot

Design And Evaluation Of Distributed Bragg Reflector From 1d Photonic Crystal Using Zemax And Teraplot

spectra of the dielectric multilayer. Multilayer dielectric mirrors are used primarily to reflect a narrow range of frequencies incident from a particular angle or particular angular range [4,7]. A dielectric mirror, also known as a Bragg mirror, is a type of mirror coatings usually based on the periodic layer system composed from two materials, one with a high index and the other low index material with thickness of quarter wavelength at normal incidence. By careful choice of the type and thickness of the dielectric layers, one can design ultra-high mirrors with reflectivity values of 99.999% or better over a narrow range of wavelengths called band-stop [8] . A Bragg mirror is also known as a distributed Bragg reflector (DBR). It has a high reflectivity around a particular wavelength defined as design wavelength. The range of wavelengths that are reflected is called the photonic stop band[8]. Within this range of wavelengths, light is "forbidden" to propagate in the structure. Recently , DBR with a complete TE and TM band gap was achieved [9]. Distributed Bragg reflectors are critical components in vertical cavity surface emitting lasers(VCSEL's) and other types of narrow-line width laser diodes[10,11] such as distributed feedback (DFB) lasers and distributed bragg reflector (DBR) lasers. They are also used to form the cavity resonator (or optical cavity) in fiber lasers and free electron lasers [12], spontaneous emission [13], high- reflecting omni-directional mirrors [14,15], and low- loss-waveguiding [16], all-optical transistors, amplifiers, routers photonic integrated circuits, optical computing [17].In this paper , reflectance of 1D PC of periodic structure was studied with the aid of Zemax software follows by Teraplot as graphical method . Further, the effect of construction parameters and angle of incident of light also investigate.
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Hybridization of Surface Plasmon Polariton and Photonic Crystal Modes in Bragg Mirror with Periodically Profiled Metal Film

Hybridization of Surface Plasmon Polariton and Photonic Crystal Modes in Bragg Mirror with Periodically Profiled Metal Film

(“1D PhC/sinusoidal profiled Au/GaAs”) in order to iden- tify the resonances with large Q-factor and peak inten- sity for use in sensorics. The dependence of light trans- mittance through structure “1D PhC/sinusoidal profiled Au/GaAs” as function of in-plane component of the wave vector and photon energy is presented in Fig. 2 for both polarisations of light with the direction of periodicity lying in the plane of incidence. The structure parameter were chosen in the way that allows to observe the formation of 1D photonic bandgap in an energy range of 1.4 ÷ 2.2 eV. In the simulations for Bragg mirror, we used λ BM = 700 nm,
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Photonic crystals as functional mirrors for semiconductor lasers

Photonic crystals as functional mirrors for semiconductor lasers

The main driving factors for the development of quantum-dot lasers were low threshold, high temperature stability and single frequency operation all arising from the delta function density of states. Very low thresholds were achieved [54] after two major fabrication breakthroughs. The first of these was to stack multiple quantum-dot layers on top of one another to increase the available modal gain [55]. The other breakthrough was to place each quantum-dot layer inside a quantum-well to prevent exciton escape from the quantum-dots due to thermal excitation [56]. Temperature stability of the threshold current at room temperature was also observed after this second breakthrough. One area where quantum-dot lasers have not lived up to their theoretical promise, however, is single frequency operation. This is because the fabrication process described above results in an inhomogeneous distribution of dot sizes and a resulting inhomogeneously broadened emission spectrum as depicted in figure 5.2.
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Design of bent photonic crystal fiber supporting a single polarization

Design of bent photonic crystal fiber supporting a single polarization

The design of a SMSP PCF is reported here, devel- oped by exploiting the differential bending loss and then analyzed through the use of a rigorous full-vectorial FEM. In this study, initially, the bend- ing of the PCF has been assumed to be in the X–Y plane. This work has shown that, for this asymmetry arrangement, the TM modal loss is higher than that of the TE mode. However, the differential LR in- creases with any excessive bending beyond a critical value of the bending radius. Such a critical bending radius can be tuned with a suitable adjustment of the value of d 2 =Λ . The LR increases with the number
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Statistical Design Centering Optimization of 1D Photonic Crystal Filters

Statistical Design Centering Optimization of 1D Photonic Crystal Filters

The nanotechnology revolution led to a size reduction in all electronics and optoelectronic devices. The dimensions of such devices are in nano-meters and parts of them reached the size of few atoms [17]. The target of optimization techniques is to suggest the numerical values of the parameters that lead to the best and optimum performance of the device or circuit. From the fabrication point of view for nanoscale dimensions, such achieved optimum values for thickness of layers must be considered as guide lines for fabricating such structures with the closest thickness to the theoretically obtained ones. This is because, we are, in fabrication, restricted by the size of atoms and this size differs from material to another. However, for any obtained thickness, an approximate value to the nearest practical one will not affect the yield obtained as it has been already taken into account in the problem formulation.
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Design and Fabrication of Photonic Microstructures by Holographic Lithography and Pattern Transformation

Design and Fabrication of Photonic Microstructures by Holographic Lithography and Pattern Transformation

nano- and microstructures in large scale. However, unwanted defects during assembly and the limited accessible structure configurations make it questionable for application of self-assembly methods for high performance devices. Top-down fabrication approaches, including layer-by-layer lithography, 15-17 two-photon or multi-photon polymerization, 18-20 glancing angle deposition 21 , and direct laser writing, 22,23 construct the desired structures in a serial manner. They are advantageous to fabricate arbitrary structures with controlled defects. However, these processes are time-consuming and expensive, and require careful registrations between layers. A non-conventional lithographic technique, holographic lithography (HL), 24-31 has been developed a decade ago as a highly efficient method to fabricate periodic microstructures defect-free over a large area (up to cm 2 ). It involves the generation of a stationary periodic light intensity profile by the interference of multiple coherent light beams. The interference pattern is transferred into a light sensitive medium, such as a photoresist, to yield the structure. In theory, the size and shape of the fabricated structures can be controlled through the proper arrangement of laser beams. However, in practice, the obtained structures could be distorted due to the refraction effect at the air/film interface, anisotropic shrinkage of the photoresist attached to a substrate, and experimental errors in optical setup. In turn, the photonic properties could be degraded. Therefore, it is critical to consider these factors in the design of the optical setups to compensate the distortion in fabrication of 3D photonic structures.
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Design, Simulation & Optimization of 2D Photonic Crystal Power Splitter

Design, Simulation & Optimization of 2D Photonic Crystal Power Splitter

Now a day, from the idea of controlling light by means of Photonic Crystal (PC) has led to many proposals and implementations for novel devices including different types of power splitters has generated wide interests in the communication field. This is possible only for peri- odic variation of the refractive index causes photonic band gap and artificially introduced defects to divide the input power equally into the output channels without significant reflection or radiation losses with compact in size. The traditional limitation on power splitter based

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The Design of Bending Long Period of  Photonic Crystal Fiber Grating Sensors

The Design of Bending Long Period of Photonic Crystal Fiber Grating Sensors

Photonic crystal fiber grating is a new passive material with many unique light transmission characteristics, it may have special applications in optical fiber communication and optical fiber sensing, where the bending long-period photonic crystal fiber grating will exist in roads, bridges and buildings potential applications. The resonance wavelength expression of PCF LPG is derived herein, the resonance wavelength shift of the grating will be associated with the grating deformation and the specific PCF LPG made materials, the PCF LPG grating refractive index profile and the transverse and longitudinal strain will result in PCF long period grating bending, thus the resonance wavelength drift of PCF LPG are ultimately lead, the degree of bending of LPG. PCF can be detected by the resonant wavelength drift.
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Tuneable Photonic Fiber Bragg Grating for Magnetic Field Sensor

Tuneable Photonic Fiber Bragg Grating for Magnetic Field Sensor

The 651.3 nm laser source is used for testing the functionality of the PCF. The fiber clamps are used to hold the PCF. The end of the PCF is placed in front of the laser source and the other end in front of an optical signal analyser (OSA) (Thorlabs-CCS200) for data analysis and recording. The OSA is a wavelength scanning device that can record the output detected power for each wavelength. It has internal charge coupled device (CCD) line array with 3648 pixel. It is also auto compensated for dark current noise and amplitude corrected. This OSA is sensitive to wavelengths ranges from 200 nm to 1000 nm. Different parameters can be varied for optimizing the output detected power. The OSA is used for detecting the output power of the desired wavelength before and after fabrication. The sensitivity of this OSA gives accurate data for sensing the effect of the FBG. When the light from the laser source entered the PCF, The fabricated Bragg grating in the PCF will reflect the wanted Bragg wavelength, so the OSA from the other end of the PCF will show the exact amount of power that is transmitted from these Bragg grating therefore Bragg reflected wavelength can be obtained from the transmission spectrum. The reflected wavelength couldn’t be seen because it must have an optical circulator.
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