An integrated high-resolution ratio-metric wavelength monitor (RMWM) is demonstrated on SOI platform. The device consists of a reconfigurable demultiplexing filter based on cascaded thermally tunable microring resonators (MRRs) and Ge-Si photodetectors integrated with each drop port of the MRRs. The MRRs are supposed to achieve specific resonant wavelength spacing to form the “X-type” spectral response between adjacent channels. The ratio of the two drop power between adjacent channels varies linearly with the wavelength in the “X-type” spectral range, thus the wavelength can be monitored by investigating the drop power ratio between two pre-configured resonant channels. The functional wavelength range and monitor resolution can be adjusted flexibly by thermally tuning the resonant wavelength spacing between adjacent rings, and an ultra-high resolution of 5 pm or higher is achieved while the resonant spacing is tuned to 1.2nm. By tuning the resonant wavelength of the two MRRs synchronously, the monitor can cover the whole 9.6nm free spectral range (FSR) with only two ring channels. The power consumption is as small as 8 mW/nm. We also demonstrate the multi-channel monitor that can measure multi-wavelength-channel simultaneously and cover the whole FSR by presetting the resonant wavelengths of every MRR without any additional power consumption. The improvements to increase the resolution are also discussed.
Proc. SPIE. 9142, Selected Papers from Conferences of the Photoelectronic Technology Committee of the Chinese Society of Astronautics: Optical Imaging, Remote Sensing, and Laser-Matter Interaction 2013
Since full-polarization parameter measurement can not be well combined with hyperspectral imaging technology yet , a new full-polarization hyperspectral imaging measurement structure using a dual optical path system was investigated. We utilized the hyperspectral1 interference imaging technology and polarization modulation technology based on electro-optic effect in our research. The polarization information, spectral information and spatial image information were acquired at the same time, which means the simultaneous measurement of hyperspectral information and full-polarization parameter was achieved. In this artical, the principle of the full-polarization parameter measurement was introduced at first. Then the experiment setup was shown and the optical elements were illustrated. Also,the detailed formula derivation steps of the full-Stokes vector was given. At last, some computer simulation data and experimental results were given. Through the combination of spectral imaging and full-polarization parameter measurement, the detecting information of the object is greatly enriched. This work will definitely be helpful to many optical remote sensing technology areas such as resources survey, environmental monitoring and military reconnaissan.
In this work, we propose a method to measure the Mueller matrix of biological tissues rapidly. Firstly, the effect of
biological tissues on the incident light can be represented as absorption, phase retardance and depolarization. This paper
defines four parameters as absorption coefficient, phase retardance coefficient, depolarization proportion and azimuth of
incident light, respectively. Secondly, we decompose the incident light into two parts: one is totally depolarized, the
other is absorbed and its phase is retarded. The two processes are characterized by two corresponding Mueller
submatrixes. Then two Mueller submatrixes are derived based on the relation between the Stokes vectors of incident
light and output light. Moreover, on the basis of a linear combination of the two Mueller submatrixes, we obtain the
Mueller matrix of biological tissues, which contains the unknown parameters. Lastly, we employ the pellicle cell of
magnolia for the sample and acquisition of it's polarization images. Then this paper applies the method to construct
calculation model from the image data. And just 6 intensity measurements are needed to calculate the four parameters.
In recent years, it has been demonstrated that polarization measurement is more informative than intensity measurement.
As a result, acquisition and detection of polarized information is applied widely in various fields such as remote sensing,
medical treatment and soon. However, most detect applications for the polarized information, and linear polarizer is
described as the key device. Therefore, only linear polarized light information can be detected and other polarization is