Precisely positioned light-induced self-written (LISW) polymeric optical waveguide for optical transceiver module fabrication

Abstract

Plastic fibers (POFs) are beginning to replace electrical wiring in many automotive and home applications. In view of this, we have reported the inexpensive wavelength-division-multiplexing (WDM) device for POF system using the LISW waveguide. The LISW waveguides are an attractive and a low-cost process for realizing self alignment between a POF and a waveguide. In this study, we have investigated about the method for precisely aligned LISW polymeric waveguides by using an optical solder effect. The optical solder effect makes it possible to realize a waveguide connection between two faced fibers by radiating from both sides even if a significant gap and a small degree of misalignment exist. When we utilize POFs with core diameters of 700μm, waveguides are combinable on the condition that an offset is 700μm or less and a gap is from 6mm to 13mm. By applying this effect, we fabricated precisely positioned LISW waveguides for devices. The fiber ends were set at certain mounting positions with respect to the LEDs and PDs. And we evaluated the positioning accuracy. The resulting positional accuracy at the extremities of the waveguides is less than one-tenth of the fiber core diameter. This value is sufficiently accurate to realize passive alignment. And this result creates new possibilities for boosting the yield of modules in mass-production.