Optical filters can be used in nearly every field from land to space. To get good performance optical filter, it is important to measure and control the film thickness of every layer on the substrate. There are many methods to monitor thin films' thickness in real-time. The most important one is the optical monitoring techniques. To avoid changing monitoring substrate frequently, we usually change the monitoring wavelength, and judge the film thickness of every layer at shut-turning point of the electric signal that represents the real-time film thickness. In the same time, Computer can be used to auto count the number of the turning point, then shut the electric source and the baffle when the counted number of the turning point arrives at the setting one. The electric signal which represents the real-time film thickness is affected by many aspects, such as optical noise, electric noise deposit rate and etc. It is not easy to judge the turning point accurately. Hence, it is useful to apply Fuzzy logic to judge the Shut-turning point of each layer in the process of manufacturing the optical filters. We design a fuzzy controller for thin film thickness monitoring which considered about both film thickness deposit rate and noise. A table for the shut-turning point judgment is set up in fuzzy logic. Then we can use computer to judge the turning point by looking up the table in real-time. This monitoring system has been applied in many projects to manufacture optical filters and got good results. Therefore, real-time monitoring film thickness using fuzzy logic is a good technique for film thickness monitoring.
Active (or tunable) waveguide devices are essential elements to control light for information processing (e.g., coding-decoding,
routing, multiplexing, timing, logic operations, etc.) in high-density integrated-optic circuits. In these devices,
the complex effective refractive index of the structure is varied in order to produce a phase or intensity modulation. In
this paper we study a micron-size metal-oxide-semiconductor (MOS)-based high index-contrast SOI waveguide for highspeed
electro-optic modulation on strong light confinement. The light confinement enhances the effect of small index
changes on the transmission of the device, enabling an ultracompact structure with high modulation depth. We study the
electrical and optical characteristics of this type of silicon electro-optic waveguide modulator using a MOS
configuration, and calculate the device's performance for electro-optic modulation with high frequency under different
modes of operation of the MOS diode and gate oxide thickness. The studied core Si electro-optic modulation device with
high frequency will bring big improvement in the field of optic communication and optic calculation.
A new detecting system of low responsibility detector surface respond is introduced. The testing principle of detector surface respond detecting by laser modulation is given. The instrument consists of a modulation laser, focusing optical system, a week current amplifying circuit, two dimensions movement flat, the data acquisition, computer interface circuit and related software. The critical part of instrument is a focusing optics system with φ5mm aperture and a narrow frequency amplification with 1 MHz frequency. The interface chip of USB is CY7C68013-128TQPF which controls the sampling of the signal and disposing data. The CPLD controls modulating laser, FIFO time and two dimension flat. The result of experiment indicates that the system offers an excellent way for selecting detector of good characteristic and analyzing detectors' respond characteristic. Also it can be used to detect manufacturing, apply heat detector and analyze characteristic of heat detector fields.
A thermal camera consists of 1024-element MCT line wavelength IRFPA with reading electrocircuit made in china. It is presented the composing of this infrared thermal camera and some key question of this thermal camera: 1) nonuniformity correction; 2) Correction of lines and rows. With same axial transmission optics and a 1-D equality angle scanner and 1024X1600 pixels per frame.the scan efficiency of the sensor is over 88% and the half periods of scanner is 5 seconds. we developed a IR instrument. the main technic target is followed: optics calibre: 90 mm, focus: 270.6 mm, identifiaction ratio:170 urad, wave band: 2-2.5um, the half period: 5 second, NEΔρ: 0.8%.