Lightwave Microsystems Corporation

Cypress Semiconductor Corporation

Qualcomm Mems Technologies, Inc.

Lightwave Microsytstems Corporation

Farnaz Parhami

Fan Zhong

Liang Zhao

Suryaprakash Ganti

Koorosh Aflatooni

Alice Liu

Pamela Shiell Trammel

Jongik Won

Nizar S Kheraj

Zhigang Zhou

This disclosure provides systems, methods and apparatus, including computer programs encoded on computer storage media, for a display with inactive dummy pixels. A display apparatus may include subpixels having a first electrode layer and a second electrode layer. The first electrode layer of an edge subpixel may include an opening, which may be made large enough to prevent the edge subpixel from actuating. The size of the openings also may be selected to attain a desired overall reflectivity for an array of edge subpixels. For example, the size of the openings may be selected to make the reflectivity of an edge pixel array similar to the reflectivity of a routing area.

Inactive dummy pixels

In one embodiment, an integrated circuit device includes an active area encompassed by a seal ring. The seal ring may include a deep moat formed on an outer edge of the seal ring. The deep moat may have a depth that extends substantially to the substrate to prevent cracks from propagating into the active area. Alternatively or in addition, the seal ring may include redundant vias.

Seal ring for preventing crack propagation in integrated circuit devices

A method and apparatus for controlling waveguide birefringence by selection of a waveguide core width for a tuned top clad is described herein. In one example, a dopant concentration within a top cladding material is between 3-6% (wt.). Given a tuned top cladding composition, a width of the waveguide core is pre-selected such that birefringence is minimized, i.e., a zero, or near zero. The desirable width of the waveguide core is determined by calculating the distribution of stress in the top cladding over a change in temperature. From this distribution of stress, a relationship between the polarization dependent wavelength and variable widths of the waveguide in the arrayed waveguide grating are determined. This relationship determines a zero value, or near zero value, of polarization dependent wavelength for a given range of waveguide widths. Accordingly, the width of the waveguide may be selected such that the polarization dependent wavelength is minimized.

Method and apparatus for controlling waveguide birefringence by selection of a waveguide core width for a top cladding

A method and apparatus for controlling waveguide birefringence by selection of a waveguide core width for a tuned top clad is described herein. A tuned top cladding describes a pre-existing dopant concentration within a top cladding material. Given a tuned top cladding composition, a width of the waveguide core is pre-selected such that birefringence is minimized, i.e., a zero, or near zero. The desirable width of the waveguide core is determined by calculating the distribution of stress in the top cladding over a change in temperature. From this distribution of stress, a relationship between the polarization dependent wavelength and variable widths of the waveguide in the arrayed waveguide grating are determined. This relationship determines a zero value, or near zero value, of polarization dependent wavelength for a given range of waveguide widths. Accordingly, the width of the waveguide may be selected such that the polarization dependent wavelength is minimized.

Method and apparatus for controlling waveguide birefringence by selection of a waveguide core width for a top clad

One aspect of the invention relates to a PLC containing at least one waveguide on a bottom clad layer, each waveguide having a top cap layer on an upper surface thereof, and a top clad layer over the waveguides having the top cap on the upper portion thereof. The presence of the top cap reduces waveguide birefringence and resultant polarization dependence in PLCs, particularly for reducing polarization dependent wavelength shift in AWGs. Another aspect of the invention relates to methods of making PLCs involving forming a waveguide layer on a bottom clad layer, forming a top cap layer on the waveguide layer, patterning the waveguide layer and the top cap layer using a mask to form waveguides having a top cap on an upper portion thereof, and forming a top clad layer over the waveguides having the top cap on the upper portion thereof.

Top cap process for reducing polarization dependent wavelength shift in planar lightwave circuits

A method of making an optical waveguide structure for an active PLC device having a reduced dn/dt birefringence. The method includes the step of forming a waveguide core layer on a bottom cladding, the waveguide core layer having a higher refractive index than the bottom cladding. The waveguide core layer is then etched to define a waveguide core. A top cladding is subsequently formed over the waveguide core and the bottom cladding. The top cladding also has a lower refractive index than the waveguide core. The top cladding is then etched to define a first trench and a second trench parallel to the waveguide core. The first trench and the second trench are configured to relieve a stress on the waveguide core. This stress can be induced by a heater, as in a case where the active PLC is a thermo-optic PLC. The first trench and the second trench can extend from an upper surface of the top cladding to an upper surface of the bottom cladding. The first trench and the second trench can extend from the upper surface of the top cladding into a portion of the underlying substrate. The first trench and the second trench are configured to balance a tensile stress within the waveguide core. A cap can be formed over the waveguide core prior to forming the top cladding to further balance the tensile stress within the waveguide core. The bottom cladding can have a higher dopant concentration than the top cladding.

Method and system for reducing dn/dt birefringence in a thermo-optic PLC device

A method of making a polarization insensitive optical waveguide structure. An optical core layer is formed on a substrate, wherein the optical core layer has a higher refractive index than the substrate. A mask is formed over the optical core layer. The unmasked areas of the optical core layer are then over-etched to define the core, wherein the over-etching removes the unmasked area of the optical core layer and a portion of the substrate disposed beneath the unmasked area, and defines the optical core. The mask is subsequently removed from the optical core. A cladding layer is then formed over the optical core and the substrate, the cladding layer having a lower refractive index than the optical core, to form a polarization insensitive optical waveguide structure. The amount of over-etching can be controlled to control an amount of substrate disposed beneath the unmasked area of the optical core layer that is removed. The amount of substrate removed, in turn, controls the polarization sensitivity of the optical waveguide structure. The amount of the portion of the substrate removed during the over-etching can be determined to minimize the polarization dependent wavelength shift and the polarization dependent loss of the optical waveguide structure. The amount of the portion of the substrate removed during the over-etching can be determined in accordance with a blanket stress of the cladding layer. The over-etching can be within a range between 7.5 percent and 30 percent.

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Fremont, CA, United States of America

Farnaz Parhami