New horizontal frustum optical waveguide fabrication using UV proximity printing

Lin, Tsung‐Hung; Yang, Hsiharng; Shyu, Ruey Fang; Chao, Ching‐Kong

doi:10.1007/s00542-007-0525-8

Cited by 8 publications

(5 citation statements)

References 21 publications

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“…Several process parameters impact on the development rate, such as resist thickness, softbake, rehydration, air temperature and humidity, and developer concentration. Previous tests showed that, for the process conditions of table 1, the threshold doses are D 0 = 350 and D 100 = 4500 mJ/cm 2 , for a resist film of 12 µm thick, where D 0 is the minimum absorbed light dose before the resist begin to develop, and D 100 is the maximum dose the resist is The simulation was carried out by using the model presented in previous section (equations [7][8][9]. The optical transmittance of an input image of a dark field line/space mask pattern was generated, as shown in figure 3.…”

Section: Resultsmentioning

confidence: 99%

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Process Modeling and Fabrication of Microlens Array in Thick Photoresist

2011

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In this work, the design and fabrication of a low f-number cylindrical microlens array is presented. The lenses were fabricated in thick photo resist of 12 μm thickness, using a contact printer exposure through a mask with a repetitive 6 μm line - 4 μm space pattern. Numerical calculations based on scalar diffraction theory were employed to model the light propagation inside the resist, determining the aerial image as a function of its thickness. Than the resist response characteristics, expressed by its contrast curve, and absorption rate were used to obtain a cross section profile. A good match between numerical and experimental results were found.

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Section: Resultsmentioning

confidence: 99%

“…The contact exposure of a thick resist works like a proximity printing mode exposure. Many authors have been exploring proximity printing technique, in several fields of MEMS and MOEMS applications (3)(4)(5)(6)(7)(8)(9)(10)(11).…”

Section: Introductionmentioning

confidence: 99%

Process Modeling and Fabrication of Microlens Array in Thick Photoresist

2011

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“…Due to the phase transformation caused by the ellipsoid microlens, the diffraction pattern of a laser diode will change from elliptical to circular. The ellipsoid shape of a microlens with variable radii may have the effect of improving the wavefront match between the propagating laser beam and the fiber model [16]. A semiellipsoid microlens can be placed onto the tip of a single-mode fiber end to improve the power coupling efficiency from a laser diode.…”

Section: Discussionmentioning

confidence: 99%

Semiellipsoid microlens fabrication method using the lift-off and alignment exposure processes

Hung¹,

Hung²,

Shen³

et al. 2012

J. Micromech. Microeng.

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We present a new semiellipsoid microlens fabrication method using the lift-off and alignment exposure processes. The lift-off method is used to create an elliptical base before the thermal reflow process. During the photoresist thermal reflow process, the elliptical base can precisely define the bottom shape of the liquid photoresist, and fabricate the semiellipsoid microlens array with a large height and small radius of curvature. The prolate spheroid approximation method is developed to estimate the thickness of the elliptic photoresist column required by the semiellipsoid microlens of a certain height, with the error being controlled within ± 3%. Electroforming technology is then used to convert the photoresist patterns into a metallic mold for a PDMS ellipsoidal microlens. The experiment results show that the geometries of a semiellipsoid microlens can be accurately defined by three parameters: the length of the major axis of the elliptical base, the length of the minor axis of the elliptical base and the thickness of the elliptical photoresist column. The proposed fabrication method facilitates mass production to achieve a high-yield and high-coupling semiellipsoid microlens that is suitable for use in commercial fiber transmission systems

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“…An optical fiber has larger dimensions and is circularly symmetrical with a mode radius of about 4.5 μm. The main problems associated with coupling light from an LD into an optical fiber lie in the mismatch between the mode profiles of the laser and the fiber, as well as establishing the alignment between them [1]. The primary challenge for these optical devices results from the extremely stringent submicron alignment tolerance required for high-efficiency coupling.…”

Section: Introductionmentioning

confidence: 99%

Semiellipsoid microlens fabrication method using UV proximity printing

Hung

Shen

et al. 2012

Appl. Opt.

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We present a new semiellipsoid microlens fabrication method that controls the printing gap in the UV lithography process without thermal reflow. The UV proximity printing method can precisely control the curvature radius ratio of the semiellipsoid microlens in the fabrication process. The proposed fabrication method facilitates mass production to achieve a high-yield and high-coupling semiellipsoid microlens that is suitable to be used in commercial fiber transmission systems. A semiellipsoid microlens can be tipped on a single-mode fiber end to improve power coupling efficiency from laser diodes. The semiellipsoid microlens allows increasing the fiber spot size and numerical aperture. It is very important to control the geometric parameters in the assembly procedure to increase the optical coupling efficiency between the laser diode and single-mode fiber. Wide misalignment tolerance, low loss, and low manufacturing cost could be achieved by the proposed fabrication method. The theoretical model is first developed to predict the optical coupling efficiency for various microstructure geometries of semiellipsoid microlens and assembly parameters in this study. Then, the Taguchi method is applied to obtain the optimal geometric parameters setting. The results show that optical coupling efficiency could be significantly improved by using the optimal geometric parameters setting.

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New horizontal frustum optical waveguide fabrication using UV proximity printing

Cited by 8 publications

References 21 publications

Process Modeling and Fabrication of Microlens Array in Thick Photoresist

Process Modeling and Fabrication of Microlens Array in Thick Photoresist

Semiellipsoid microlens fabrication method using the lift-off and alignment exposure processes

Semiellipsoid microlens fabrication method using UV proximity printing

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