Photoelectric devices and microsystem
2018, 47(2): 220002.
doi: 10.3788/IRLA201847.0220002
In order to obtain wide-band and high-resolution monochromatic light, the wavelength of the imaging spectrometer was calibrated, and a scanning monochromator was designed. The grating scanning system was driven by worm and worm wheel mechanism, and an off-axis installation method was designed to install the worm gear, thus solving the problem of the traditional installation method, such as the decrease of the effective aperture of the grating, and the increase of the stray light. The monochromator optics system used the horizontal Czerny-Turner structure. It used three gratings to achieve 280-2 240 nm wide band output, which achieved the high diffraction efficiency and guaranteed the spectral resolution in the whole wavelength range. The output wavelength and the motor step number was non-linear in the process of worm gear scanning, so the monochromator system was calibrated by different mathematical models. The final experiment and the measurement proved that the spectral resolution of the monochromator was better than 0.1, 0.2, 0.4 nm at 280-560 nm, 560-1 120 nm, 1 120-2 240 nm respectively. Simultaneously the wavelength repeatability reached to 0.094, 0.186, 0.372 nm, and the precision reached to 0.096, 0.191, 0.382 nm. The monochromator achieves the design goals, and meets the requirements of the wavelength calibration of the imaging spectrometer.
2018, 47(2): 220003.
doi: 10.3788/IRLA201847.0220003
Micro-distance spectra splitting is a key technology for compact dual-band imaging system in infrared field. Utilizing the Fresnel diffraction theory and angular spectrum theory, the diffractive properties of dual-wavelength and wide angle light passing through stepped phase grating in fractional Talbot distance were theoretically investigated. A typical scheme of imaging structure based on dual-array detection pixels was set up, where two light beams with different wavelength incident after passing through the stepped phase grating. The numerical simulation shows the splitting results of incident 4 m and 4.5 m wavelength light with-30 to 30 angle, including the distribution of luminous intensity, energy and signal-to-noise ratio on dual-array detection pixels. Our results are beneficial not only for designing the compact dual-band optical imaging structure, but also for building up precision spectral separating component.
2017, 46(4): 420002.
doi: 10.3788/IRLA201746.0420002
The connected defective elements in Focal Plane Array (FPA) were tested by optical microscopy and FPA test-bench. The reasons of forming connected defective elements in FPA were studied. Results show that it is difficult to identify connected defective elements by optical microscopy. And it is also difficult to identify connected defective elements by FPA response testing bench because the response voltage of connected defective elements is basically the same as that of normal elements. The connected defective elements can be identified effectively by FPA crosstalk testing bench because the crosstalk between connected defective elements is 100%, which is obviously different from that of the normal elements. At this point, the response voltage of connected defective elements is average of that of the normal elements. The tables with connecting or the electrodes with connecting caused by the process of photolithography and eroding result in the generation of the connected defective elements. As well as the indium bump with connecting caused by the process of photolithography and lift-off also leads to the generation of the connected defective elements. Fabrication process such as photolithography, eroding and lift-off was optimized to reduce connected defective elements.
2016, 45(S2): 101-105.
doi: 10.3788/IRLA201645.S220001
Low light level night vision goggle has been benefit to pilot for carrying out terrain reconnaissance, making up air flight, and air-to-ground attacking at night. Image intensifier assembly can intensify the low light image projected by object at night to bright one fitted to be observed by human. According to the spectral response of image intensifier, NVIS compatible characteristic and spectrum matching performance of super-second and the third generation low light level image intensifier assembly was analyzed. Operational performance of different night vision goggles was derived by calculating formula. It is shown that the third generation low light level image intensifier assembly has better NVIS compatible characteristic than super-second generation by means of good spectrum matching performance and high quantum efficiency, which is benefit to reconstruct the NVIS compatible cockpit lighting. Meanwhile, because of higher signal to noise ratio, night vision system equipped the third generation low light level image intensifier assembly can discover farther object than the second generation.
2016, 45(S2): 106-109.
doi: 10.3788/IRLA201645.S220002
The high performance phosphor screen can effectively enhance the performance of low light level image intensifiers. The performance of phosphor screen mainly depends on the nature of the powder layer. The powder layer is essentially formed by the accumulation of phosphor grains, and therefore the related character research of the powder layer based on powder stacking theory is helpful to guide the actual production process to obtain higher quality powder layer, thereby enhancing the performance of the screen. Therefore, a theoretical analysis of the powder layer density based on the classic powder stacking theory was made, and combined with the actual production, some further related studies for the best powder layer thickness were obtained, taking a certain type of phosphor for example. The result shows that the powder layer first should be possible to achieve the optimum thickness, and then make the density to the maximum, so can obtain the better powder layer, hence, the performance of phosphor screen will get better.
2016, 45(S1): 183-187.
doi: 10.3788/IRLA201645.S120001
A squeezed high birefringence Photonic Crystal Fiber (PCF) with high negative flattened dispersion characteristics was proposed. In order to obtain the high birefringence characteristics, the cladding of PCF was made of squeezed triangular lattice and elliptical air holes. In order to improve the flexibility of controlling the dispersion, the core of PCF was added into a small defect air hole. The birefringence and dispersion characteristics were analyzed by super lattice method. The simulation results show that the designed PCF offers ultra flattened negative dispersion (-6677 psnm-1km-1) in a broad range of wavelengths from 1.3 m to 1.8 m, the birefringence can be reached the magnitude of 10-2 and the high birefringence can be reached 2.2110-2 at 1.55 m. Based on the high negative dispersion and high birefringence characteristic, PCF will be widely used in optical transmission system and optical fiber sensing.
2016, 45(S1): 188-193.
doi: 10.3788/IRLA201645.S120002
An advanced avalanche photodiode(APD) was put forword which was integrated by the Si Separate Absorption, Charge, Multiplication(SACM) and Ge SACM APDs. This advanced APD has enlarged the detected wavelength range to 200-1 400 nm. Furthermore, the key parameters which were used to characterize the APD performance, such as the electric field distribution, the dark current and photocurrent, the gain, and the sensitivity of the APD were researched. The simulation results demonstrated that the breakdown voltage of the advanced APD is 145 V, the peak response is 22 A/W at 900 nm wavelength as cathode is 140 V, and the current gain of the advanced APD could get 50 at 400 nm wavelength before breakdown. The fabrication process was also discussed.
2016, 45(9): 920001.
doi: 10.3788/IRLA201645.0920001
The development of the optically addressed spatial light modulator (OASLM) was reported. Its structure and working principle was introduced in detail. Meanwhile, the photosensitive response curve, static wave-front distortion and temporal waveform distortion was investigated in detail in the process of experiment. Besides, OASLM was successfully demonstrated in the online experiment. The results show that OASLM not only has the ability to achieve the desired transmittance distribution, but also has no additional effect on the high-power laser system. Finally, the shaping effect of spatial filter in the laser system was analyzed. The result shows that the size of spatial filter was also an important factor which determined the shaping precision when this device was used in high power laser systems.
2016, 45(9): 920002.
doi: 10.3788/IRLA201645.0920002
Complicated battlefield electromagnetic environment seriously affects the safety, reliability and technical index of airborne electro-optical platform. Electromagnetic shielding of minitype airborne electro-optical platform was designed in order to improve its battle efficiency. Firstly, the shielding effectiveness of electromagnetic shielding was expounded. Design of electromagnetic shielding was carried out for minitype airborne electro-optical platform from the aspects of circuit board, ABS shell, gaps and video transmission. The shielding effects were verified by electromagnetic compatibility test. The test results show that the video image is normal, conduction emission value is reduced by about 20 dBV, radiation emission value was reduced by about 10 dBV/m, and other items test are improved to varying degrees, which provide a reference for the design of electromagnetic compatibility for minitype airborne electro-optical platform.
2016, 45(8): 820001.
doi: 10.3788/IRLA201645.0820001
The transverse mode and transmission properties in frequency region of 1-100 GHz of a microstrip transmission line model based on nematic liquid crystal (LC) were studied. The influences brought by the distribution of dielectric anisotropy of liquid crystal on the solution and S-parameter of microstrip line were researched through the finite element method accurately and comprehensively, as well as the influences of the bias voltage. Simulation results indicate that the distribution property reduce the echo loss of microstrip line, which is obtained in consideration of the distribution of dielectric anisotropy of liquid. Besides, the S-parameter changes continuously since the voltage between the strip and the gound gradually increases while the resonant frequency moves the same way. Moreover, this accurate method can amend the motion of resonant frequency by 2.4 GHz, compared with the results obtained by those methods in the past. This paper provides a theory basis for researches in the field of LC microwave devices.
2016, 45(8): 820002.
doi: 10.3788/IRLA201645.0820002
A new microwave photonic filter based on stimulated Brillouin scattering was proposed. By tuning the center wavelength of the optical filter, the switchability between the microwave photonic bandpass filter and the microwave photonic notch filter can be obtained. The passband or the notch center frequency of the microwave photonic filter can be tuned continuously by tuning the wavelength of the pump laser. Since no electrical component was involved, the microwave photonic filter was all-optical. Therefore it can achieve a very broadband operating frequency range. The maximum measured tuning frequency range in the experiment was limited by the displaying range of the vector network analyzer. Since an optical phase modulator was used, no bias voltage was needed. Therefore, there was no bias voltage drift problem. Experimental results demonstrate a switchable and continuously tunable microwave photonic filter with a broadband operating frequency range from 9-26.5 GHz. The bandpass filter has a narrow 3 dB bandwidth up to 28 MHz, which is limited by the optical fiber Brillouin gain linewidth.
2016, 45(8): 820003.
doi: 10.3788/IRLA201645.0820003
Integration of optical devices onto silicon substrate is attracting increasing attention in the field of optoelectronics. The fluidic self-assembly technology was applied to the integration of thin-film metal-semiconductor-metal (MSM) photodetector, the integration results was related to the geometry of the binding site. The spacing and shape of the binding sites on the thin-film MSM photodetector will affect the integration process of device onto the host substrate. In order to effectively predict the effect, MATLAB was used to simulate the distribution of interfacial free energy for the integration process. Firstly, based on the introduction of thin-film MSM photodetector and its integration, a model of translation and rotation during the integration was established for the simulation. Then, according to the linear relationship between the interfacial free energy and the matching degree, the distribution of the matching degree was investigated for the different binding sites with the different spacing and shape. By analyzing the relationship between the slope of the matching degree and the correct-assembly/false-assembly state, it predicted that the integration results would be better when the spacing between the binding sites is longer and the shape of the binding sites is trapezoid. Finally, considering that the thin-film optical devices may have specific requirment of positive and negative contacts, the binding sites with asymmetric shape was designed to avoid the reverse binding connection during the integration process.
2016, 45(8): 820004.
doi: 10.3788/IRLA201645.0820004
To start from microchannel-plate photoelectric multiple model, constraint conditions for vacuum multiplier system caused by anodized transmission of composite waveguide and position-sensitive anodes were studied deeply, and Mott interpolation method was employed to research the electro-optical properties of new optoelectronic device. Firstly, structure and working principle of composite waveguide anode were introduced, and the correspondence between the transmission anode and position-sensitive anode was given. On this basis, constrained relationship between high-speed signal detection and precise positioning of incident light axis was analyzed, and the corresponding devices design and experimental methods were given. Finally, the verification testing of the new device was conducted in vacuum furnace. Test results show that the new device is feasible both in theory and practice,to search for the adaptive adjustment mechanism of interelectrode tunneling voltage is a trend as inevitable for extending its application field.
2016, 45(7): 720001.
doi: 10.3788/IRLA201645.0720001
A tunable optical filter(TOF) based on MEMS technology was designed. The broadband optical signal was first dispersed by a grating and then the wavelength corresponding to the passband of the TOF was selectively reflected to the output by a MEMS torsion mirror, thus the optical filtering and wavelength tuning functions were realized. A single mode fiber(SMF) was employed as the input and a multimode fiber (MMF) or few mode fiber(FMF) was employed as the output, thus the passband of the TOF was characterized by narrow-band and flat-top. After parameter optimization, the simulation results show that the 0.5 dB and 20 dB bandwidth are 0.95 nm/0.29 nm and 1.39 nm/0.69 nm with MMF and FMF employed, which meet the requirements by DWDM systems of 100 GHz and 50 GHz channel spacing, respectively. The output is MMF or FMF, the optical signal passing through the TOF cannot be further transmitted in SMF. The output can just be received by a photo detector, thus this TOF is usually applied as the outputs of the nodes in all optical network.
2016, 45(7): 720002.
doi: 10.3788/IRLA201645.0720002
Performance differences between Offner convex grating imaging spectrometer and Dyson concave grating imaging spectrometer, both with concentric structure, was analyzed under different grating constants. The diffraction angle expressions of the two spectrometers were obtained, and their diffraction characteristics were acquired. Both of the spectrometers were designed and analyzed by ZEMAX, under F number of 2.5, spectral rage of 8-12 m, spectral resolution of 15.6 nm, and grating constants of 100 m and 50 m. The two structures could both meet the system requirements using spherical mirrors in the case of a higher grating constant. Offner's volume is 7 times larger than Dyson's, and Offner's weight is about Dyson's 1/13. When grating constant turned lower, Dyson could still meet the requirements just with spherical mirrors, while Offner must adopt aspherical mirrors and make an off-axis design for the requirements. The Offner's volume is 7 times larger than Dyson's, and Offner's weight is about Dyson's 1/11. The results show that Offner form and Dyson form have advantages and disadvantages in the aspect of operability of machining, volume, and weight. In the selection of spectrometer, the choice should be made depending on the specific application requirements.
2016, 45(7): 720003.
doi: 10.3788/IRLA201645.0720003
Surface-plasmon-enhanced GaN-LED was proposed based on the multilayered rectangular nano-grating, which was deposited by periodic raster silver thin film in the gas material. A model was theoretically established, which was enhancing the internal luminous efficiency of LED, the SPPs radiant matching and the SPPs radiant declining. The experiment shows that the structure of the deposited silver thin film can improve the luminous efficiency because of the SPPs enhancement. Polarized mode of the emergent light has no effect on the luminous efficiency of LED; Metal raster absorptivity will achieve the peak if the duty ratio is about 0.87; SPPs potentiation can dramatically improve the luminous efficiency and nonlinear process. The research on the improvement of the LED luminous efficiency has theoretical and practical significance.
2016, 45(7): 720004.
doi: 10.3788/IRLA201645.0720004
Because of the high electron mobility and two-dimensional electron gas concentration, InP based pseudomorphic high electron mobility transistors(PHEMTs) become one of the most promising three-terminal devices which can operate in terahertz. The InAs composite channel was used to improve the operating frequency of the devices. The two-dimensional electron gas(2DEG) showed a mobility of 13000 cm2/(Vs) at room temperature. 70 nm gate-length InAs/In0.53Ga0.47As InP-based PHEMTs were successfully fabricated with two fingers 30 m total gate width and source-drain space of 2 m. The T-shaped gate with a stem height of 210 nm was fabricated to minimize parasitic capacitance. The fabricated devices exhibited a maximum drain current density of 1440 mA/mm(VGS=0.4 V) and a maximum transconductance of 2230 mS/mm. The current gain cutoff frequency fT and the maximum oscillation frequency fmax were 280 and 640 GHz, respectively. These performances make the device well-suited for millimeter wave or terahertz wave applications.
2016, 45(5): 520001.
doi: 10.3788/IRLA201645.0520001
Based on space applications, avalanche photodiode (APD) optimal gain control was investigated in terms of space borne laser range finder. By introducing current SNR(signal to noise ratio) model, the key factors were analyzed which mainly affects SNR of APD in space borne laser range finder. According to special application of space borne laser range finder, optimal gain control of APD was studied. Temperature feedback control circuit for APD optimal gain was designed, temperature digital feedback control algorithm for APD optimal gain was deduced, and the validity and temperature adaptability of the control circuit and the algorithm were demonstrated. It is shown from the experiment that, because of the designed control circuit and algorithm, the gain factor of APD maintains is constant in the temperature range from -25℃ to 60℃, which meets the requirement for space borne applications.
2016, 45(5): 520002.
doi: 10.3788/IRLA201645.0520002
In order to study the dark current of the devices, in this paper, the dark current of In0.83Ga0.17As p-i-n photodiodes was analyzed. Extended wavelength In0.83Ga0.17As p-i-n photodiodes with mesa type configuration were fabricated by two different processes. The first process(device marked M135L-5) was: rapid thermal annealing (RTA) was performed after mesa etching. The second process(device marked M135L-3) was: RTA was performed before mesa etching. Dark current mechanisms for extended wavelength In0.83Ga0.17As p-i-n photodiodes with different device fabrication processes were studied by means of the current-voltage curves at different temperatures and bias voltages. In contrast to M135L-5, M135L-3 had a lower dark current at the same test temperature from 220 K to 300 K. The ratio of perimeter-to-area(P/A) was used to characterize the perimeter-dependent leakage current and the area-dependent leakage current. The results show that M135L-3 has a lower area-dependent leakage current. Activation energy of devices served as a method to estimate the dark current composition was extracted from current-voltage curves. The results indicate that the dark current of M135L-5 is dominated by diffusion current at reverse 0.01-0.5 V bias voltage and at 220-270 K. The dark current of M135L-3 is dominated by diffusion current at 250-300 K as well as dominated by generation recombination current and surface recombination current at reverse 0.01-0.5 V bias voltage and at 220-240 K. Meanwhile, the results of dark current fitting also show the same conclusions. The studies have shown that M135L-3 with annealing treatment and optimization process is better than M135L-5 for reducing dark current because the RTA decrease the bulk dark current.
2016, 45(5): 520003.
doi: 10.3788/IRLA201645.0520003
Electro-optic modulator is one of the most important components for optical communication system. Its performance determines the transmission performance of an optical communication system. For the electrode, its structures, species and designs have a significant influence on the property of modulator. For designing and researching the electrode of novel electro-optic modulator based on FBG, the relationship among the overlap of mode field, structural parameters of electrode and FBG's center wavelength shift were discussed in this paper by numerical calculation methods. It has a significance of manufacture of polymer electro-optic modulators based on FBG, and promotes the development of electro-optic modulator.
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