Fabrication Steps for a POF-WDM Key-Element

Abstract

Optical simulation software based on the ray tracing method offers easy and fast results in imaging optics. This method can also be applied in other fields of light propagation, e.g. non-imaging optics. In this paper a miniature spectrometer designed and developed by means of ray tracing will be discussed. Compared to the classical optical design, requirements for optimal design of this element differ particularly with regard to the spatial separation of the different wavelengths and the complete transmission of light to achieve the best signal-to-noise ratio. The basis of the presented element is a Rowland spectrometer. But for the complete guidance of light that emerges the entrance split the design of this element has to be changed fundamentally, especially when a high numerical aperture of the light beam is taken into account. A monolithic approach is presented with a blazed grating based on an aspheric mirror to suppress most of the aberrations. The grating is analyzed for different diffraction orders and the best possible efficiency. On the exit of this element the light must be guided into different photo diodes with different effective areas. In general, the element should be designed in a way that it can be produced with a mass production technology like injection molding in order to offer a reasonable price. The paper will describe the development of this miniature spectrometer step by step by means of ray tracing simulations.

Keywords

• wdm
• polymer optical fibers
• multiplexing
• raytracing
• rowland spectrometer