A Novel Spot-Size Converter with Asymmetric Taper for Deep-Ridge Waveguide Devices

2019 ◽  
Author(s):  
Takuo Hiratani ◽  
Naoya Kono ◽  
Tomokazu Katsuyama ◽  
Ryuji Yamabi ◽  
Yuhki Itoh ◽  
...  
Keyword(s):  
Spot Size ◽  
Ridge Waveguide ◽  
Waveguide Devices

An Overgrowth-Free Design for InGaAlAs Spot-Size-Converted Ridge Waveguide Lasers

2007 ◽  
Vol 19 (13) ◽  
pp. 975-977 ◽  
Author(s):  
D. Klotzkin ◽  
Jia-Sheng Huang ◽  
Hanh Lu ◽  
Trinh Nguyen ◽  
T. Pinnington ◽  
...  
Keyword(s):  
Spot Size ◽  
Ridge Waveguide ◽  
Waveguide Lasers ◽  
Ridge Waveguide Lasers

scholarly journals Design of Polarization-Independent Coarse Wavelength Splitters Based on Ridge-Waveguide Directional Couplers

2011 ◽  
Vol 2011 ◽  
pp. 1-9 ◽  
Author(s):  
Chee-Wei Lee
Keyword(s):  
Planar Waveguide ◽  
Filter Design ◽  
Optical Network ◽  
Ridge Waveguide ◽  
Passive Optical Network ◽  
Polarization Splitter ◽  
Directional Couplers ◽  
Waveguide Devices ◽  
Wavelength Filter ◽  
Polarization Independent

We present the first unique design of a polarization-independent dual-wavelength splitter for wavelengths around 1.3 μm and 1.55 μm that is potentially of great interest to passive optical network (PON) applications. The filter design is simple compared with the other architectures and is based on ridge-type lateral directional couplers that can be readily integrated with other planar waveguide devices. Two design examples, based on InP/InGaAsP and Si/SiGe waveguides, are given. This polarization-independent wavelength splitting is achieved by exploiting the polarization dependence of the waveguides to produce coupling lengths that are sensitive to polarization and wavelength. We show that, to split the wavelengths without splitting the polarizations, the coupling lengths must be sufficiently different for TE and TM and for the different wavelengths in order to give the correct required ratios between the TE and TM coupling lengths for the two wavelengths of interest. We also show that the same approach can be applied to the design of a polarization splitter. The crosstalk, optical bandwidth, and fabrication sensitivity for the wavelength filter are evaluated.

Analysis of the thermo-optic effect in lateral-carrier-injection SOI ridge waveguide devices

2010 ◽  
Vol 31 (6) ◽  
pp. 064009 ◽  
Author(s):  
Zhao Jiate ◽  
Zhao Yong ◽  
Wang Wanjun ◽  
Hao Yinlei ◽  
Zhou Qiang ◽  
...  
Keyword(s):  
Ridge Waveguide ◽  
Carrier Injection ◽  
Waveguide Devices

Remarks on the application of backscattered electron imaging (BEI) to the scanning electron microscopy (SEM) of biological structures

1983 ◽  
Vol 41 ◽  
pp. 484-487
Author(s):  
Etienne de Harven
Keyword(s):  
High Resolution ◽  
Incident Beam ◽  
Spot Size ◽  
Primary Electron ◽  
Critical Point Drying ◽  
Cell Shapes ◽  
High Resolution Images ◽  
Backscattered Electron ◽  
Electron Imaging ◽  
Scanning Electron

Biological ultrastructures have been extensively studied with the scanning electron microscope (SEM) for the past 12 years mainly because this instrument offers accurate and reproducible high resolution images of cell shapes, provided the cells are dried in ways which will spare them the damage which would be caused by air drying. This can be achieved by several techniques among which the critical point drying technique of T. Anderson has been, by far, the most reproducibly successful. Many biologists, however, have been interpreting SEM micrographs in terms of an exclusive secondary electron imaging (SEI) process in which the resolution is primarily limited by the spot size of the primary incident beam. in fact, this is not the case since it appears that high resolution, even on uncoated samples, is probably compromised by the emission of secondary electrons of much more complex origin.When an incident primary electron beam interacts with the surface of most biological samples, a large percentage of the electrons penetrate below the surface of the exposed cells.

A High Resolution Scanning Microscope

1968 ◽  
Vol 26 ◽  
pp. 356-357
Author(s):  
A. V. Crewe ◽  
J. Wall ◽  
L. M. Welter
Keyword(s):  
High Resolution ◽  
Field Emission ◽  
Spherical Aberration ◽  
Focal Length ◽  
Spot Size ◽  
Emission Source ◽  
Field Of View ◽  
Scanning Microscope ◽  
Magnetic Lens ◽  
High Quality

A scanning microscope using a field emission source has been described elsewhere. This microscope has now been improved by replacing the single magnetic lens with a high quality lens of the type described by Ruska. This lens has a focal length of 1 mm and a spherical aberration coefficient of 0.5 mm. The final spot size, and therefore the microscope resolution, is limited by the aberration of this lens to about 6 Å.The lens has been constructed very carefully, maintaining a tolerance of + 1 μ on all critical surfaces. The gun is prealigned on the lens to form a compact unit. The only mechanical adjustments are those which control the specimen and the tip positions. The microscope can be used in two modes. With the lens off and the gun focused on the specimen, the resolution is 250 Å over an undistorted field of view of 2 mm. With the lens on,the resolution is 20 Å or better over a field of view of 40 microns. The magnification can be accurately varied by attenuating the raster current.

Image registration with a computer driven S.T.E.M.

1978 ◽  
Vol 36 (1) ◽  
pp. 98-99
Author(s):  
A.M.H. Schepman ◽  
J.A.P. van der Voort ◽  
J.E. Mellema
Keyword(s):  
Spot Size ◽  
Scanning Transmission Electron Microscope ◽  
Small Computer ◽  
Structural Studies ◽  
Area Of Interest ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Specimen Area ◽  
On Line ◽  
Minimum Distances

A Scanning Transmission Electron Microscope (STEM) was coupled to a small computer. The system (see Fig. 1) has been built using a Philips EM400, equipped with a scanning attachment and a DEC PDP11/34 computer with 34K memory. The gun (Fig. 2) consists of a continuously renewed tip of radius 0.2 to 0.4 μm of a tungsten wire heated just below its melting point by a focussed laser beam (1). On-line operation procedures were developped aiming at the reduction of the amount of radiation of the specimen area of interest, while selecting the various imaging parameters and upon registration of the information content. Whereas the theoretical limiting spot size is 0.75 nm (2), routine resolution checks showed minimum distances in the order 1.2 to 1.5 nm between corresponding intensity maxima in successive scans. This value is sufficient for structural studies of regular biological material to test the performance of STEM over high resolution CTEM.

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