Eiji Okuda

Multiple imaging and multiple Fourier transformation using planar microlens arrays.

A new type of multiple imaging and multiple Fourier transformation system under coherent illumination using microlens arrays has been developed. The optical system is based on geometrical optics instead of convolution or diffraction. As a result, it has the advantage of design flexibility especially in alignment of the duplicate images. The experimental results of the system, which are implemented using planar microlens arrays fabricated by an ion exchange technique, are also discussed.

Planar gradient-index glass waveguide and its applications to a 4-port branched circuit and star coupler

Planar gradient-index glass waveguides with nearly circular cross sections have been fabricated by the ion migration method. A low-loss branched circuit and star coupler are demonstrated.

High numerical aperture planar microlens with swelled structure

The planar microlens is a 2-D integrated microlens fabricated by the selective ion exchange technique. This paper demonstrates a new class of planar microlens which has a high numerical aperture. The new planar microlens uses a swelling structure and index distribution which comes from replacing ions with different ion volumes. Lens diameters from 10 to 400 microm can be fabricated. A numerical aperture larger than 0.5 is achieved when the lens diameter is smaller than 100 microm. Use of this microlens in light coupling between an LD and a single-mode fiber is also evaluated.

Aberration Properties Of The Planar Microlens Array And Its Applications To Imaging Optics

Aberration properties of planar microlens arrays, which are small lenslet arrays fabricated by an ion exchange technique, are described. The optical set-up of the measurement system. is designed to combine a Mach-Zehnder interferometer, a microscope imaging set-up and fringe scanning analysis to obtain precise measurements for microlenses. Many types of planar microlens have been measured, and the spherical aberration, coma in off-axis imaging etc., were evaluated. The experimental results indicate that the planar microlens can perform high quality imaging in a wide image field. Also, by using planar microlens arrays, multiple imaging optical systems in incoherent and coherent illumination are demonstrated..© (1989) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Optical Guided-Wave Oil Leak Sensor

From safety considerations an all-optical waveguide-type oil leak sensor would be advantageous in hazardous enviroments such as Oil Refineries. The all-optical oil leak sensor is expected to be intrinsically safe, since any electrical or electronic type sensor always runs the risk of igniting combustable gases and possibly causing a serious explosion [1].