We present a simple technique to determine the design parameters of an optical interconnect system that uses integral planar lenses. The technique is based on the ABCD transformation matrix method. This analysis technique is significantly simpler and more efficient than the previously published methods for finding the design parameters and predicting the coupling efficiency of the system. The proposed method is applied to compute the coupling efficiency of single- and two-level optical systems.
An approximate analytical solution involving the evaluation of the overlap integral method has been developed to
estimate the coupled optical power in a multilevel optical system. The transmitter and receiver optics are located on
different planes, vertically separated by a distance Z. 45º micro-mirror pairs are used to facilitate out-of-plane reflection
of the optical beam in order for the transmitter and receiver components to be optically linked. The optical components
consist of planar waveguide focusing elements, involving a combination of graded-index effect and lens front curvature.
Optical signal in many active and passive optical devices can be well approximated by a Gaussian beam. The coupling
loss formulas have been derived to support elliptical and circular Gaussian beam analysis. Spot size mismatch, non-ideal
propagation distance, axial offset, mirror angular deviation and relative tilt between the two planes are major
contributors toward optical power loss in a multilevel optical system. The derived coupling loss formulas has been
applied to find the optimal coupling condition like micro-mirror positions, Z, relative distances of optical elements from
the micro-mirror, beam spot size, etc. for a prototype system. BPM simulation results are in good agreement with the
numerical results obtained by the approximate analytical solutions. The derived coupling loss formulas can be used to
estimate optimal optical power loss in a single level or multilevel optical system in MOEMS based optical circuits as
well as in a conventional optical system where paraxial approximation is assumed.
A silica micro-lens pair has been proposed which can be integrated
with planar optical waveguide circuits. The lens pair enables an
optical signal to travel in free space between two opposing planar
waveguides with minimal optical loss. Each lens in the lens pair
consists of a slab GRIN lens with a convexly shaped front face. This paper briefly reviews the micro-lens design process and reports progress in fabricating the device. The characterisation of the GRIN
layer and masking experiments used to evaluate the deep oxide etch
are presented. A selectivity of 250:1 was achieved for the deep oxide etch using a NiCr mask.
A silica microlens has been proposed which can be integrated with planar optical waveguide circuits. In order to fabricate the microlens, two deep silica etches must be performed. RIE is the prefered process as under certain conditions it is anisotropic. This paper reports on a study of different masking materials and plasma etch conditions trialed for the deep silica etch.
This paper reports on the scalability of MEMS optical cross-connect (OXC) switches which use 2D planar waveguide architecture and an integrated waveguide lens to enhance free space propagation. The optical loss, total device area and ease of integration with MEMS micromirrors are considered for three competing layout configurations.
This paper describes the results of simulation studies for the design of an integrated collimating waveguide lens pair. The lens pair has application in MOEM based optical switches which rely on the free space propagation of an optical beam over a matrix of micro-mirrors. Consideration is given to the simulated tolerance to various misalignment and processing errors.