We present a novel all-glass wafer-level lens manufacturing technology. Compared to existing wafer-level lens manufacturing technologies, we realize lenses all in glass, which has a number of distinct advantages, including the availability of different glass types with largely varying dispersion for efficient achromatic lens design. Another advantage of all-glass solutions is the ability to dice the lens stack to match the form factor of a rectangular sensor area without compromising the optical performance of the lens, thereby allowing to significantly reducing the footprint of an array camera.
We will present recent advances in Kaleido Technology on the
ultra-precision diamond-milling process, which is an
extremely versatile tool for manufacturing of masters for wafer-based replication technologies. Diamond-milling has the
advantage of being able to manufacture lenses with much larger radii of curvatures compared to etching methods.
Spherical-, aspherical- and free-form-surfaces have been machined with form accuracies better than 200 nm (PV), arrays
up to 50 x 50 mm have been manufactured on wafers, with lens-position accuracies better than 3 μm absolute over the
We present a general 3-D spectral collocation method for the analysis of diffractive optical elements (DOEs). The method computes a direct solution to the Maxwell's equations in the time domain. The computational domain is decomposed into a number of small subdomains in which a high-order Chebyshev spectral collocation scheme is used to approximate the spatial derivates in Maxwell's equations. The local solutions in each subdomain are integrated using a Runge-Kutta scheme, and the global solution is reconstructed by using the characteristic variables of the strongly hyperbolic set of equations. A smooth mapping technique is used to correctly model curvi- linear boundaries thus making the method a strong tool for analyzing, e.g., grating couplers with analog surface reliefs. The accuracy and efficiency of the method is verified using simple test cases and examples of the analysis of analog grating couplers of finite length are given. The examples demonstrate the superior properties of the method such as the low number of points per wavelength needed to accurately resolve wave propagation and the absence of numerical dispersion.
Diffractive optical elements comprising sub-wavelength aperiodic surface reliefs of finite length require the use of rigorous solvers for Maxwell's equations. We present a detailed analysis of Focusing Grating Couplers (FGC's) using a recently introduced 2D spectral collocation method. The method, solving Maxwell's equations in the time domain, is based on a high-order Chebyshev collocation scheme has the advantage over traditionally used Finite Difference methods that much fewer points per wavelength is needed to accurately resolve wave propagation in diffracting structures. At the same time, the new method exhibits no numerical dispersion in contrast to, e.g., the Finite Difference Time-Domain method. In this presentation we analyze a number of sub-wavelength FGC's with lengths of up to 1000 wavelengths. The FGC's use analog surface reliefs due to their superior diffraction properties. For structures yielding a perpendicular out- coupling, we find that typically 10 - 12 collocation points per wavelength is sufficient. We find that the focal length depends strongly upon the depth of the surface relief, e.g. that a significant shift of the focal plane from the value expected from geometrical optics is seen if deep surface reliefs are used.
The use of a shielded microstrip-configuration for polymer- based electro-optic modulators has the advantage over an open microstrip geometry that the modulator is pacified with respect to environmental conditions. We investigate such a shielded modulator numerically. Employing the Laplace equation the quasi-TEM field distribution is calculated and by employing Wheeler's incremental rule we determine the conductor loss due to the skin effect. We demonstrate that the use of a shield in combination with a buffer layer with a low dielectric constant yields the modulator insensitive to geometrical variations. For a modulator with a wide driving electrode the maximum bandwidth may be as high as 90 GHz.
The design of integrated optical S-bands, power splitters, and directional couplers are described in terms of normalized parameters. These parameters are calculated accurately by a numerical method leading to general design curves for fiber-compatible waveguide devices.
A numerical analysis of microwave and optical properties of a polymer-based travelling-wave integrated electro-optic modulator is presented. We propose a new structure with a microwave buffer layer on top of the driving electrode. This buffer layer is added in order to obtain phase velocity matching between the optical field and the microwave modulation field. Employing the Effective Index Method and the 2D Beam Propagation Method the optical properties is investigated and the optical modulation index and the driving voltage is determined. Employing the Spectral Domain Approach we investigate the microwave properties of the new structure in a configuration with a travelling-wave electrode. It is shown that the two characteristics: the microwave mode index and the characteristic impedance, can be varied independently for the proposed structure. From the optical and microwave properties the active characteristics of a Mach-Zehnder interferometer based on the waveguide structure is investigated. We show that with no restrictions on the electrical power consumption, the optical modulation bandwidth can be higher than 100 GHz. This bandwidth will be reduced to 34 GHz, if a restriction on the electrical power from the signal generator is imposed.