Uniform Loss Arrayed Waveguide Grating

With the advantages of excellent performance, compact structure and easy integration, arrayed-waveguide grating (AWG) is highly valued as one of the most promising wavelength division multiplexing devices and has a very wide range of applications. The applications of AWG are mainly classified as multiplexer, demultiplexer and the router which acts as the intermediate network node. Compared to the multi\emultiplexer, studies of AWGR are relatively few. Currently the researches of AWG mainly focus on two aspects which are improving the performances and extending the functions. The N×N AWGR plays an important role in WDM networks since it can simultaneously processing N2optical channels at N different frequencies, which greatly improve the transmission signal capacity.For the N×N wavelength router network, the free spectral range (FSR) of AWG is required to be N times the channel spacing, which represents that all the channels of a FSR should be applied. However the insertion losses of the peripheral channels are3-5dB higher than those of the central one in the traditional design which is not only unable to meet the communication requirement but also cannot realize the cyclic characteristics. Then it is essential to improve the insertion loss uniformity for AWGR.With a view to increasing the insertion loss uniformity, many methods have been proposed such as ULCF-AWG. But those methods have side effect such as inducing additional intrinsic loss or increasing the size of device. In this paper we proposed a new method to achieve the cyclic AWGR with uniform channel insertion loss over the entire FSR. By appropriately adjusting the point orientation of waveguide arrays, the peak energy will be dispersed to the entire output waveguides instead of the central one. Comparing the simulated spectral response of the conventional design and the design referred in our paper, it is obvious that our design can improve the channel insertion loss uniformity for AWG.Finally the fabrication processes based on the planar lightwave circuit for AWG are introduced; the fabrication and uniform loss characteristics for AWG are achieved.