TM-pass glass waveguide polariser with periodic multilayer claddingoverlaid with isotropic dielectric media

A novel TM-pass waveguide polariser, the cladding of which consists of a periodic dielectric multilayer overlaid with a fully-thick isotropic dielectric layer with a higher refractive index, is proposed for integrated optics formed on a glass substrate. As the periodic multilayer is used as birefringent media, it seems that the proposed waveguide polariser becomes more compact and stable, and cheaper, compared with a hybrid waveguide polariser using birefringent crystal as the cladding. TM-pass waveguide polarisers using alumina-silica periodic multilayers thinner than 20 μm have been designed. It has been theoretically confirmed that an extinction ratio of ⩾20 dB and insertion loss of ⩽0.001 dB can be achieved     

Analysis of the ${rm TE}$ -Pass or ${rm TM}$-Pass Metal-Clad Polarizer With a Resonant Buffer Layer

A metal-clad optical polarizer with a resonant buffer layer has been investigated by the finite-element method in this paper. Important waveguide design parameters, such as the refractive index, thickness, interaction length, fabrication tolerance, and band-stop characteristics, have been analyzed in detail. Mode coupling within the polarizer and the losses due to coupling between the polarizer and the input and output waveguides are considered using the normal mode analysis. The loss behaviors of and modes are explained and the roles of the resonant buffer layer are interpreted. By using ultralow index layers, resonance, as well as its phase-matching conditions and excellent performance, has also been presented and discussed for this structure for the first time. Simulations show that high performance can be achieved in a wide range of the cladding thicknesses (ges 2 mum) and interaction length for both TE-pass and TM-pass polarizers. With optimized parameters under 3-mm length, it is possible to obtain a broadband TE-pass polarizer with an extinction ratio of more than 40 dB and insertion loss below 0.2 dB over 200 nm, and a TM-pass polarizer with an extinction ratio of more than 30 dB and insertion loss below 0.4 dB over 28 nm.     

Poling-induced waveguide polarizers in electrooptic polymers

In order to demonstrate polymeric waveguide polarizers, photobleached polymer waveguides supporting both TE and TM modes are integrated with poling induced polymer waveguides that support either TE or TM modes. Fabrication parameters like UV exposures and poling voltages are controlled to reduce excess losses due to the mode profile mismatch between the connected waveguides. A TM-pass polarizer is realized by poling the polymer in the vertical direction. For TE-pass polarizer the polymer is poled horizontally by using four poling electrodes which enhance the uniformity of the poling field direction. The measured excess loss is less than 0.5 dB, and polarization extinction ratios for TM-pass and TE-pass polarizers are 20.7 dB and 17.1 dB, respectively.     

Fiber-Optic Polarizer Using Resonant Tunneling through a Multilayer Overlay

We demonstrate an in-line fiber-optic polarizer using resonant tunneling through a leaky multilayer overlay for the first time. Polarization extinction ratio (PER) ? 27 dB with an insertion loss (IL) ? 3 dB has been demonstrated experimentally with scope of further improvement. A simple planar waveguide model is developed to analyze the device whose predictions match very well with the experimental results. It is further shown that by properly selecting the device parameters one can achieve PER ? 68 dB with IL ? 0.2 dB for λ = 0.6328 μm and PER ? 80 dB with IL ? 1.2 dB for λ = 1.3 μm.     

基于Bragg光栅的超高消光比SOI波导偏振器设计

波导偏振器是片上集成相干光学系统中的关键器件之一,超高消光比、低损耗、紧凑型波导偏振器的设计一直是研究的热点。基于绝缘体上硅平台的倾斜Bragg光栅被用于实现超高消光比波导偏振器结构。利用一维光子晶体能带理论分别计算TE和TM模式光的能带结构分布,选择TE模式禁带与TM导带重叠带隙设计光栅,可实现TM模式低损传输,而TE模式被Bragg光栅高效反射,从而产生超高偏振消光比。3D FDTD仿真表明:16 μm倾斜Bragg光栅波导偏振器可在中心波长1550 nm附近70 nm的带宽内,实现大于37 dB的超高消光比,器件的损耗小于0.64 dB;进一步增加光栅周期数,当长度为25 μm时,消光比可提高至46 dB。Bragg光栅倾斜角与刻蚀宽度偏差仿真表明:设计的结构加工误差容限较大,同时该结构仅需一次曝光刻蚀,工艺流程简单。     

Integrated optical waveguide polarizer based on photobleaching-induced birefringence in an electrooptic polymer

A TE-pass waveguide polarizer is fabricated by utilizing the photobleaching-induced birefringence at room temperature in an electrooptic polymer. The polarizer consists of the photobleached waveguide supporting only TE mode, which is integrated in the middle of the etched rib waveguide supporting both TE and TM modes. It has a simple structure and requires no high temperature process like poling. The measured polarization extinction ratio is about 21 dB at the wavelengths of 1.3 and 1.55 /spl mu/m, and the estimated excess loss is about 0.4 dB.     

Integrated optical waveguide polarizer on glass with a birefringentpolymer overlay

An integrated optical waveguide polarizer on glass is described. It is based on a filtering zone propagating only TE mode whereas the TM mode leaks out into a birefringent polymer simply deposited on the glass. The polymer is poled by a corona process. The measured polarization extinction ratio between TE and TM modes is better than 39 dB and the excess loss due to the filtering zone is less than 4 dB. The total loss is in the order of 7 dB     

Single-Mode Fiber-Type Polarizer

The simple and novel fabrication technique of the fiber-type polarizer has been demonstrated and the polarization characteristics of the polarizer have been investigated. The polarizer structure consists of the eccentric core and the metal coat on the thin buffer layer whose thickness is controlled by chemical etching. The maximum extinction ratio of 41 dB (polarizer length L = 40.8 mm) was obtained at Lambda = 1.15 µm when the buffer layer thickness was about 0.3 µm. Although the insertion loss increases with decreasing the buffer layer thickness, the insertion loss of 0.66 dB was obtained with the extinction ratio of 22 dB (polarizer length L = 21.4 mm). An aluminum coat was superior to a gold coat for low propagation loss and a high extinction ratio.     

ARROW-type polarizer utilizing form birefringence in multilayerfirst cladding

A waveguide polarizer using an ARROW (antiresonant reflecting optical waveguide) structure, of which the first cladding consists of three thin layers, is proposed. Theoretical calculation shows that this polarizer can achieve isolation over 30 dB/cm with an insertion loss of 0.01 dB/cm at 1.3 μm. Isolation of 83 dB/cm with insertion loss of 4.3 dB/cm was experimentally obtained at 0.633 μm. This structure is suitable for the integration of a polarization splitter and photodetector     

Low-loss TM-pass polariser fabricated by proton exchange for z-cut ti:LiNbO3 waveguides

We fabricated a low-loss TM-pass polariser at ? = 1.32 ?m integrated with low-loss titanium waveguides in Z-cut LiNbO3. The polariser, fabricated by proton exchange, had an excess insertion loss of 0.3 dB and a polarisation extinction ratio of > 40dB.     

ARROW-B type polarization splitter with asymmetric Y-branchfabricated by a self-alignment process

We have proposed and demonstrated a polarization splitter based on an ARROW-B type waveguide. This device has an asymmetric Y-branch configuration, connecting a waveguide with a large modal birefringence to a low-birefringent waveguide which is channeled by a stripe lateral confinement structure. The device can achieve a high extinction ratio without precise mask alignment, since these two waveguides are connected by a self-alignment process. In addition, a low insertion loss is achieved because of adiabatic Y-branching. We designed this device at the wavelength of 1.55 μm and fabricated it using RF sputtering. As a result, high extinction ratios of -19.4 dB for TE mode and -19.0 dB for TM mode were achieved     

TE-pass and TM-pass waveguide polarisers with buried birefringentpolymer

TE-pass and TM-pass waveguide polarisers in polymer waveguides using a buried layer of highly birefringent polyimide are presented. The two polarisers are fabricated based on a consistent process to insert polyimide for the buried ribs in TE-pass polarisers and for lateral cladding in TM-pass polarisers: respectively. Polarisation extinction ratios of 35 and 40 dB are obtained for the TE-pass and TM-pass polarisers, respectively     

Laminated polarizers exhibiting high performance over a wide rangeof wavelength

A laminated polarizer exhibiting high performance over a wide range of wavelengths has been fabricated for the first time. The polarizer consists of alternate layers of laminated silica film and metal-included semiconductor ultra-thin film as the transparent and absorptive layers, respectively. Extinction ratios of greater than 50 dB with insertion losses of less than 0.4 dB have been obtained over the wavelength range of 0.8-1.55 μm. At the wavelength 0.98 μm where previously no viable laminated polarizer had been available, the extinction ratio is as high as greater than 60 dB and the insertion loss less than 0.3 dB     

A novel polarizer based on directional coupler and surface plasmon polaritons

A novel polarizer with a silver nanoribbon added into a traditional waveguide directional coupler is designed to realize the polarized output of TE mode. A high extinction ratio can be obtained because of the selectivity of surface plasmon polaritons （SPPs） on polarization. The effects of the polarizer parameters on coupling efficiency and extinction ratio are discussed. Simulation results indicate that the coupling efficiency for TE mode can reach about 95%, but only 3% for TM mode, with the extinction ratio of TE mode about 15 dB when the light wavelength is 1550 nm, The polarizer may have potential applications in photonic integrated circuits and quantum information technology.     

集成光学光纤陀螺芯片

本文首次报道了国内研制的集成光学光纤陀螺芯片,详细描述了其设计考虑与制作。单 Y 型多功能钛扩散铌酸锂芯片包含消光比大于35dB 的薄膜波导偏振器、分束比为49.5/50.5的3dB 分束器/合束器、半波电压小于5伏的相位调制器,光纤—器件—光纤插入损耗为5.4dB。     

Silica-based 8×8 optical matrix switch integrating newswitching units with large fabrication tolerance

An 8×8 optical matrix switch consisting of asymmetric Mach-Zehnder (MZ) interferometer switching units with a waveguide intersection was fabricated using silica-based planar lightwave circuits (PLC's) on a silicon substrate. This switching unit can realize a high extinction ratio and a wide operation wavelength range even if the coupling ratios of the directional couplers (DC's) consisting the switching unit, deviate greatly from the ideal value of 50%. A matrix switch with a DC-coupling ratio of 30% was fabricated to test the validity of the proposed geometry. The average insertion loss was 7.3 dB in the transverse electric (TE) mode and 7.5 dB in the transverse magnetic (TM) mode. The average extinction ratio was 31.2 dB in the TE mode and 31.3 dB in the TM mode. The wavelength range with an extinction ratio greater than 20 dB was over 100 nm     

Integrated-Optic Polarization Controlling Devices Using Electro-Optic Polymers

Integrated-optic polarization controlling devices such as polarizers, polarization splitters, and polarization converters, are proposed and demonstrated in nonlinear optic polymers. Poling-induced birefringence in electro-optic polymers is exploited to fabricate the devices. The polymeric waveguide polarizers show low excess losses, and extinction ratios of 20.7 dB and 17.1 dB for TM-pass and TE-pass polarizers, respectively. The polymeric waveguide polarization splitters exhibit TE-TM mode splittings with crosstalk of 14.2 dB and 10.1 dB for TM and TE mode splittings, respectively. The polymeric waveguide polarization converters show successful TE/TM polarization mode conversion with conversion efficiencies of higher than 30 dB. The device employs poling-induced waveguides which have slowly rotating azimuth angle of optic axis along the light propagation direction. The novel polarization converter is insensitive to wavelength and easier to fabricate than the other polarization converters containing periodic structures.     

Design and performance of a polymer Mach-Zehnder interferometer electro-optic modulator at 1.55 μm

Based on poled guest-host electro-optic (EO) polymer DR1/SU-8, a Mach-Zehnder interferometer (MZI) EO modulator operated at 1.55 μm is proposed. For achieving high response speed and high EO modulation efficiency, both waveguide structure and electrode structure are especially optimized. The impedance match and less index mismatch are achieved. The final characteristic impedance of electrode is about 49.4 Ω, and the microwave index and the light-wave index are 1.5616 and 1.6006, respectively. The device is fabricated using wet-etching technique and inductively coupled plasma (ICP) etching technique, and its performance is measured at 1.55 μm. Experimental results show that when the applied voltage is tuned, the modulator can be changed from ON state to OFF state. The insertion loss at ON state is 12 dB and the extinction ratio between ON and OFF states is about 10 dB. The high response speed is in nano-second level for a square-wave signal. Therefore, the modulator possesses potential applications in high-speed optical networks on chip.     

基于宽度调制谐振腔的光子晶体电光调制器

针对目前电光调制器插入损耗高的问题,提出了一种基于宽度调制(WM)型谐振腔的光子晶体电光调制器.该器件由输入端纳米线波导、硅基光子晶体波导和WM型谐振腔组成,前二者的连接处采用锥形结构,用于减少2种波导之间的级联损耗.根据时域耦合模理论与等离子体色散效应,采用WM型谐振腔和PN掺杂结构实现对横电(TE)模的调制,并应用...     

Polarization-independent integrated optical, acoustically tunabledouble-stage wavelength filter in LiNbO3

We report a polarization-independent integrated acousto-optical double-stage wavelength filter in X-cut, Y-propagating LiNbO₃. The device consists of a combination of four acousto-optical mode converters, a TE- and a TM-pass polarizer, and two polarization splitters; their specific design and properties are discussed. The filter has a bandwidth of 1.4 nm and a tuning range of 76 nm around λ1.55 μm. Maximum filter transmission is achieved with a RF drive power of only 80 mW; it excites via a single unidirectional transducer a guided surface acoustic wave driving the four polarization converters of both stages. Fiber-to-fiber insertion loss is 4.6 dB for TM- and 4.8 dB for TE-polarized waves. Multiwavelength filtering has been demonstrated