In this paper we present the size reduction of a 160-channel, 50-GHz Si3N4 based AWG-spectrometer. The spectrometer was designed for TM-polarized light with a central wavelength of 850 nm applying our proprietary “AWG-Parameters” tool. For the simulations of AWG layout, the PHASAR photonics tool from Optiwave was used. The simulated results show satisfying optical properties of the designed AWG-spectrometer. However, such high-channel count AWG features large size. To solve this problem we designed a special taper enabling the reduction of AWG structure by about 15%, while keeping the same optical properties. The technological verification of both AWG designs is also presented.
We present the design of 20-channel, 50-GHz Si3N4 based AWG applying our proprietary AWG-Parameters tool. For the simulations of the AWG layout we used PHASAR photonics tool from Optiwave. The simulated transmission characteristics were then evaluated applying our AWG-Analyzer tool. We studied the influence of one of the design parameters – the separation between input/output waveguides, dx on the channel crosstalk. The results show that there is some minimum waveguide separation necessary to keep the crosstalk between transmitting channels low. The AWGs were designed for TM-polarized light with a central wavelength of 850 nm. They will later be used in a photonic integrated circuit dedicated to medical diagnostic imaging applications.
The most common application of optical Y-splitters is their use in FTTx networks. It allows several customers to share the same physical medium, bringing high-speed networking, digital television and telephone services to residences using fiber-optic cables. The task of the optical splitters in such FTTH networks is to split one optical signal in many identical signals bringing for example the same TV signal in different households. Of course, the more buildings can be served by one optical splitter the lower are the installation costs. Therefore, the special attention is paid mainly to the design of high channel optical splitters presenting the serious challenge for the professional designers. In this paper a new Y-branch shape is proposed for 1×32 Y-branch splitter ensuring better splitting properties compared to the one recommended by ITU, in terms of their performance in transmission systems using wavelength division multiplexing.
It is well known that the main problem in the Y-branch splitting approach is the processing of the branching point where two waveguides start to separate. This is technologically very difficult; leading generally to an asymmetric splitting ratio causing non-uniformity of the split power over all the output waveguides. In this work we show that not only processing of branching points influences strongly splitting properties of the device but also the used waveguide structure itself. The standard low index waveguides have usually size of 6 μm x 6 μm ensuring on one side small coupling loses between fibers and waveguides and on the other side supporting mainly the single mode light propagation. However, our simulations showed that in the standard 6 μm x 6 μm waveguides is the presence of the first mode already so strong that it causes additional asymmetric splitting of the optical signals. To suppress the presence of the first mode we reduced the waveguide core size from 6 μm x 6 μm to 5.5 μm x 5.5 μm and 5 μm x 5 μm and this way were able to improve the uniformity of the split power over all the output waveguides by factor 3. Additionally, based on these results we were also able to reduce the size of the designed Y-branch to the half.