Design of High-Precision Parallel AWG Demodulation System

Abstract

Here, we present a high-precision demodulation method that supports the arrayed waveguide grating (AWG) system, which includes a 1 × 8 AWG as the primary filter with a 0.5 nm channel spacing and a 1 × 4 AWG as the auxiliary filter with a 1 nm channel spacing. The high precision is achieved through an innovative method of decoupling three channels, involving two adjacent channels of the primary filter and one channel of the secondary auxiliary filter. Simulation results show that the AWGs have a good transmission spectrum with crosstalk below −24.8 dB, non-uniformities below 0.8 dB, insertion loss below −3.7 dB, 3 dB bandwidth of 0.25 nm, and 10 dB bandwidth of 0.43 nm. The interrogation precision can reach 8 pm, with a dynamic range of 0.4 nm, corresponding to a single FBG.

Optimization Method for Center Frequency Accuracy of High-Channel-Count Arrayed Waveguide Grating in Dense Wavelength Division Multiplexing Systems

“…By comparing them, it can be observed that the optimization method proposed in this paper achieves a higher level of CFA, approximately 0.04∆f. Two research works based on the Si material platform in the table [13,33] demonstrate optimization effects on CFA similar to or even better than this study, but they both involve the addition of extra optical structures. The use of serially connected fiber Bragg grating and parallel AWG significantly increases the device size compared to a single AWG on the same material platform.…”

“…The center frequency accuracy (CFA) of AWG output channels measures the deviation between the center frequency of each channel and its ideal value. Nevertheless, the greater number of channels and narrower channel spacing pose significant challenges in the design and optimization of CFA [13,20,29,33]. Factors affecting CFA include not only manufacturing errors and operating temperatures of the devices [10,34], but also the improper selection of channel spacing parameters during the design phase of AWG [35].…”

High-Precision Continuous FBG Interrogator based on an AWG

“…Based on this structure, Yuan reported an AWG-FBG demodulation system that uses two AWGs, and the dynamic range was 28 nm with a 1.3 nm bandwidth at 3 dB 25 . Jiao 26 analysed a parallel AWG demodulation system to improve the performance, and the dynamic range was 0.4 nm with channel spacings of 0.5 nm and 1 nm. However, at the edge of the measurement range, the spectral overlap significantly decreases.…”