Topology and analysis of an N-stage cascaded polymer eight-port microring optical router with 7N channel wavelengths

Eight-port optical routers are widely used in cluster-mesh photonic networks-on-chip(No C). By using 24 groups of cross-coupling two-ring resonators, a 1-stage 8-port polymer optical router is proposed, which can optically route 7 channel wavelength data streams along definite path in two-dimensional(2D) plane. Under the selected 7 channel wavelengths, the insertion losses along all routing paths are within 0.02-0.58 d B, the maximum crosstalk of all routing operations is less than-39 d B, and the device footprint size is about 0.79 mm2. Then, a universal novel structure and routing scheme of N-stage cascaded 8-port optical router are presented, which contains 7N channel wavelengths. Because of the good scalability in wavelength, this device shows potential application of wideband signal routing in optical No C.     

Design and fabrication of a mid-infrared carbon dioxide sensor for the application in greenhouse environment

A mid-infrared carbon dioxide (CO2) sensor is presented for the application in greenhouse environment. An integrated multi-pass gas chamber and a dual-channel differential detection method are adopted to decrease response time and suppress environmental influence, respectively. An optical module is developed using a cost-effective wideband mid-infrared light source, a dual-channel pyre electrical detector and a spherical mirror, and the moisture-proof function is specially designed for enabling the application of this sensor in greenhouse with high humidity. Experiments are carried out to evaluate the sensing performance on CO2 concentration. According to the experimental results, the limit of detection (LoD) is about 3´10-5 with an absorption length of 30 cm. The relative detection error is less than 5% within the measurement range of 3´10-5—5´10-3. Based on 10 h long-term stability measurement on 5´10-4and 2´10-3 standard CO2 samples, the maximum fluctuations are 1.08% and 3.6%, respectively. By using a 2.4 GHz wireless network communication system for remote monitoring and data recording, a field measurement of this sensor in a greenhouse is conducted, and good performance is proven in such circumstance.     

A mid-infrared methane detection device based on dual- channel lock-in amplifier

A portable dual-channel digital/analogue hybrid lock-in amplifier (LIA) is developed, and its amplitude detection error is less than 10% when the signal-to-noise ratio (SNR) is larger than ?12 dB. Then, a differential mid-infrared methane (CH4) detection device is experimentally demonstrated based on a wideband incandescence wire-source and a multi-pass spherical reflector. The experiments are carried out to obtain the sensing performance of the device. With the absorption length of only ~4.8 cm, the limit of detection (LoD) is about 71.43 mg/m3, and the detection range is from 0 mg/m3 to 5.00×104 mg/m3. As the concentration gets larger than 714.30 mg/m3, the relative detection error falls into the range of ?5%—+5%. Two seven-hour-measurements are done on the CH4 samples with concentrations of 1.43×103 mg/m3 and 4.29×103 mg/m3, respectively, and the results show that the maximum relative error is less than 5%. Because of the cost effective incandescence wire-source, the small-size and inexpensive dual-channel LIA, and the small-size absorption pool and reflector, the developed device shows potential applications of CH4 detection in coal mine production and environmental protection.