Journals >Chinese Journal of Lasers
Contents
1998
Volume: 25 Issue 7
21 Article(s)
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Research Article
Analysis and Design of Optical Switch and Superlattices Photodetector Combination in Si 1-x Ge x/Si for 1.55 μm Operation
[in Chinese], [in Chinese], and [in Chinese]
A systematic analysis and optimum design have been reported for the integration of the Si1-xGex optical switch and the Si1-xGex/Si infrared detector at λ=1.55 μm. The optimizing design results are:(1) For the Si1-xGex optical switch,Ge content x=0.05. Waveguide height,width and etched depth are 3, 8.5 and 2.6 μm, respA systematic analysis and optimum design have been reported for the integration of the Si1-xGex optical switch and the Si1-xGex/Si infrared detector at λ=1.55 μm. The optimizing design results are:(1) For the Si1-xGex optical switch,Ge content x=0.05. Waveguide height,width and etched depth are 3, 8.5 and 2.6 μm, respectively, branch angles are 5～6°, and the bias voltage of pn+ junction is 0.97 V.(2) For the Si1-xGex/Si infrared detector, Ge content x=0.5. Total thickness of the detector is 550 nm, shich consists of 23 periods alternate 6 nm Si0.5Ge0.5 +17 nm Si. The length of the detector is about 1.5～2 mm. The results show that the internal quantum effciency of the detector of this structure can be as high as 80%..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 7, 596 (1998)
8×8 Multiple Quantum Well Spatial Light Modulators for Optical Interconnection
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
8×8 multiple quantum well spatial light modulators (MQW SLMs) are designed and their breakdown voltage, ASFP mode, contrast ratio and insertion loss are measured. An optical interconnection pattern is implemented in which 8×8 optical beams are generated from a semiconductor laser by using a Dammann grating an8×8 multiple quantum well spatial light modulators (MQW SLMs) are designed and their breakdown voltage, ASFP mode, contrast ratio and insertion loss are measured. An optical interconnection pattern is implemented in which 8×8 optical beams are generated from a semiconductor laser by using a Dammann grating and are routed to the 64 windows of 8×8 SLMs. Through this architecture, modulation characteristics of 8×8 SLMs can be measured..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 7, 603 (1998)
A novel Two mode Dispersion Compensating Fiber Based on LP01Mode
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Computer stimulation shows if the LP 02 mode is suppressed and only the LP 01 mode is transmitted in a two mode dispersion compensating fiber of three clad dings, more than thousands ps/nm·km negative dispersion values can be achieved. Having a large mode field, small bending loss, small polarization mode dispersiComputer stimulation shows if the LP 02 mode is suppressed and only the LP 01 mode is transmitted in a two mode dispersion compensating fiber of three clad dings, more than thousands ps/nm·km negative dispersion values can be achieved. Having a large mode field, small bending loss, small polarization mode dispersion and small temperature drift, and the loss value as other dispersion compensated fibers, the fiber of this kind appears to be a promising dispersion compensating fiber..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 7, 609 (1998)
Detection of Distortions in Transparent Media Using Light Amplification in LiNbO3:Fe Crystal
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
When there are distortions in transparent media, a light through uniform parts and distortions of the media will overlap each other after the transformation of a lens. By the amplification of LiNbO 3:Fe crystal placed at the place where the two kinds of lights coincide, the contrast of the transmitted pattern will incrWhen there are distortions in transparent media, a light through uniform parts and distortions of the media will overlap each other after the transformation of a lens. By the amplification of LiNbO 3:Fe crystal placed at the place where the two kinds of lights coincide, the contrast of the transmitted pattern will increase greatly and then we can detect the distortions in the transparent media. This method is quite simple and has high sensitivity..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 7, 613 (1998)
A New Method of Analyzing Imagings in Fog
[in Chinese], and [in Chinese]
In this paper, the transmission situation of a ballistic light carrying the information of the object image in fog is analyzed. Its intensity reduction and traveling distance limitation are discussed. This new kind of experimental method based by the characteristic of a polarized light is presented. The experimental reIn this paper, the transmission situation of a ballistic light carrying the information of the object image in fog is analyzed. Its intensity reduction and traveling distance limitation are discussed. This new kind of experimental method based by the characteristic of a polarized light is presented. The experimental result which is in good agreement with theory is given. The probabilities of increasing signal to noise ratio and enhancing the quality of an imaging in fog with this experimental method are discussed..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 7, 616 (1998)
Holography and Information Processing
Using Self imaging Functions for the Optical Interconnection of Neural Network
[in Chinese], [in Chinese], and [in Chinese]
The self imaging functions which can self image on scale are shown. Then we apply them to the optical interconnection of neural network. Consequently, the optical interconnection system is simple and the experimental operation, especially the optical adjustment is easy. Finally, the experiment is shown.The self imaging functions which can self image on scale are shown. Then we apply them to the optical interconnection of neural network. Consequently, the optical interconnection system is simple and the experimental operation, especially the optical adjustment is easy. Finally, the experiment is shown..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 7, 644 (1998)
Image Processing in Target Pointing
[in Chinese], [in Chinese], and [in Chinese]
This paper introduces a kind of image processing method for laser fusion experiment. Since the image of the hohlraum hole is dim and its brilliance distribution is non uniform a technique to determine the geometric center of the image is thus necessary. Application of the technique to the target pointing in the ShenguaThis paper introduces a kind of image processing method for laser fusion experiment. Since the image of the hohlraum hole is dim and its brilliance distribution is non uniform a technique to determine the geometric center of the image is thus necessary. Application of the technique to the target pointing in the Shenguang Ⅱ project is also included..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 7, 649 (1998)
Laser Manufacturing
Characteristics of the Sodium Layers Observed by the Laser Radar in Wuhan
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
In this paper, the mesospheric sodium data, observed from Mar. 1 to Mar. 3 1996 in Wuhan (30°32N, 114°22E) by a laser radar, have been analyzed, and the distribution of the Na atoms density with the altitude and the relation of the profiles of the Na atoms density with time have been got. The results point In this paper, the mesospheric sodium data, observed from Mar. 1 to Mar. 3 1996 in Wuhan (30°32N, 114°22E) by a laser radar, have been analyzed, and the distribution of the Na atoms density with the altitude and the relation of the profiles of the Na atoms density with time have been got. The results point out that the distributions of the Na atoms density change vs time apparently. The sodium layers lie between 80￣105 km, and the maximum Na density lies between 92￣95 km, its value varies from 1×10 9 to 3×10 9 atoms/m 3 when there are no meter rains..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 7, 653 (1998)
Microdissection of Chromosomes by a Nd:YAG Laser Microbeam and Isolation of Chromosomal Fragments in Hordeum Vulgare L.
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
A method for microdissection, isolation of chromosomal fragments using a laser beam incorporated with a microglassneedle was established. Firstly, a 7H chromosome of Hordeum Vulgare L. was dissected by the Nd:YAG laser beam of suitable parameters; then the fragment comprising a satellite was isolated and put into an A method for microdissection, isolation of chromosomal fragments using a laser beam incorporated with a microglassneedle was established. Firstly, a 7H chromosome of Hordeum Vulgare L. was dissected by the Nd:YAG laser beam of suitable parameters; then the fragment comprising a satellite was isolated and put into an eppendorf tube by a micro glassneedle fixed on a micromanipulator. This research provides a new method for the microdissection of special chromosomal regions..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 7, 657 (1998)
Studies of the Photodynamic Effects of Fullerene (C60) on DNA by FT Raman Spectroscopy
[in Chinese], [in Chinese], and [in Chinese]
The photodynamic effects of fullerene (C60) on the calf thymus DNA with FT Raman spectroscopy at the molecular level has been studied in this paper. The spectrum showed that the photoexcited C 60 damaged almost all of the component groups of DNA to different extents. The conformation of DNA has been changed considerablThe photodynamic effects of fullerene (C60) on the calf thymus DNA with FT Raman spectroscopy at the molecular level has been studied in this paper. The spectrum showed that the photoexcited C 60 damaged almost all of the component groups of DNA to different extents. The conformation of DNA has been changed considerably by weakening the bases stacking and hydrogen bond, meanwhile the adenine and guanine are destroyed greatly. With increasing the concentration, C 60 induced a cleavage of the DNA strand by damaging the phosphate backbone and deoxyribose. The photodynamic damage to DNA by photoexcited C 60 was induced from singlet oxygen(1 O 2)and ·OH, O 2·－..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 7, 661 (1998)
Optical System of a Coherent CO2Laser Radar for Edge Tracking
[in Chinese], and [in Chinese]
An optical system is designed and fabricated on the basis of the target scattering characteristics and the edge tracking concept. This system is the optical head of a frequency modualated continous wave CO2 laser radar in which only a single mode CO2 laser is used. Using a collimator tube, the tested minimum light specAn optical system is designed and fabricated on the basis of the target scattering characteristics and the edge tracking concept. This system is the optical head of a frequency modualated continous wave CO2 laser radar in which only a single mode CO2 laser is used. Using a collimator tube, the tested minimum light speckle on the focus plane is 50 μm in diameter. The acceptable error signals are engendered when a slender laser beam of 0.12 mrad angular divergence is directed on the diffuse target edge. The backscattered signals from building at 7.8 km are obtained with a fairly good SNR when the laser output is about 5W..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 7, 667 (1998)
Laser Physics
Additive Pulse Mode Locking of a Nd:LMA Laser
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
A diode laser pumped Nd:LMA laser was reported, in which a CW power of 650 mW with a slope efficiency of 33% at 1.054 μm was demonstrated. Using a fiber nonlinear additive cavity, self starting additive pulse mode locking was realized. Near transform limited pulses as short as 1.8 ps with an average power of 58 mW wereA diode laser pumped Nd:LMA laser was reported, in which a CW power of 650 mW with a slope efficiency of 33% at 1.054 μm was demonstrated. Using a fiber nonlinear additive cavity, self starting additive pulse mode locking was realized. Near transform limited pulses as short as 1.8 ps with an average power of 58 mW were obtained from the laser..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 7, 577 (1998)
A Tunable Q-switched Flashlamp Pumped Cr3+:LiCaAlF6Laser
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
In this paper, a tunable Q switched flashlamp pumped Cr 3+ :LiCaAlF6 laser is introduced. The tuning range of a Cr 3+ :LiCaAlF6 is determined to be at least 730￣850 nm. The free running lasing wavelenth of the Cr 3+ :LiCaAlF6 is 780 nm. When the input pulse energy is 292 J, the highest output energy is 1.62 J. A slopIn this paper, a tunable Q switched flashlamp pumped Cr 3+ :LiCaAlF6 laser is introduced. The tuning range of a Cr 3+ :LiCaAlF6 is determined to be at least 730￣850 nm. The free running lasing wavelenth of the Cr 3+ :LiCaAlF6 is 780 nm. When the input pulse energy is 292 J, the highest output energy is 1.62 J. A slope efficiency is 0.8%. The threshold energy is 50.4 J. The Q switching of the Cr 3+ :LiCaAlF6 is performed with a KD*P crystal. The single pulse width is 48 ns and the highest output power is 1.3×106 W..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 7, 581 (1998)
High Power External Cavity Semiconductor Laser
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The high power external cavity semiconductor laser has become an important optoelectronic device. In this paper, using a grating as the feedback component, a laser of single frequency output over 70 mW and side mode suppression over 30 dB is reported. Meanwhile, some parameters which influence the performance of the hiThe high power external cavity semiconductor laser has become an important optoelectronic device. In this paper, using a grating as the feedback component, a laser of single frequency output over 70 mW and side mode suppression over 30 dB is reported. Meanwhile, some parameters which influence the performance of the high power external cavity laser are analyzed..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 7, 584 (1998)
Investigation of He Substitution for Ar as Working Gas of an Across flow CW 2 kW CO2Laser
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
A JK 13 across flow CW 2 kW CO 2 laser of tube plan low gas pressure discharge structure, using argon helium mixing gas, was studied. The substituted amount of He gas (Ar doped amount) increased from 20% to 60%. When the working gas pressures were 2.93~4.26 kPa and the discharge currents were 3~11 A, the laser dischargA JK 13 across flow CW 2 kW CO 2 laser of tube plan low gas pressure discharge structure, using argon helium mixing gas, was studied. The substituted amount of He gas (Ar doped amount) increased from 20% to 60%. When the working gas pressures were 2.93~4.26 kPa and the discharge currents were 3~11 A, the laser discharged steadly and operated normally. An output power of 1.7 kW and an effciency of electro optic conversion of 16 percent can be obtained..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 7, 587 (1998)
High Voltage Switching Power Supply for Flashlamp pumped Ti:sapphire Laser
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
This paper introduces a switching power supply for a repetition rate flashlamp pumped Ti:sapphire laser. It includes a switching circuit at PWM mode and a double prefiring circuit. This power supply is capable of giving an output power of 2 kilowatts at a repetition rate of 5 Hz.This paper introduces a switching power supply for a repetition rate flashlamp pumped Ti:sapphire laser. It includes a switching circuit at PWM mode and a double prefiring circuit. This power supply is capable of giving an output power of 2 kilowatts at a repetition rate of 5 Hz..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 7, 591 (1998)
Anisotropic Self diffraction in Photorefractive Crystals with an External Electric Field
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Anisotropic self diffraction in doped KNSBN crystals has been observed when an external electric field is applied for the experimental configuration where the c axis is parallel to the incidence plane. The coupled wave equations and their numerical solutions including the space distribution of a grating vector and thAnisotropic self diffraction in doped KNSBN crystals has been observed when an external electric field is applied for the experimental configuration where the c axis is parallel to the incidence plane. The coupled wave equations and their numerical solutions including the space distribution of a grating vector and the second order space electric field are presented. Both theoretical analysis and experimental results show that the anisotropic self diffracted light arises from the contribution of both incident beams..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 7, 621 (1998)
Langmuir Flow Effects in Ring Laser Gyros
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The experimental results of radial distribution of Langmuir flow effects in a ring laser gyro are reported in this paper. They show that it is mainly the motion of upper and lower laser level atoms contributes to the ring laser gyro output. Therefore, the discription about the radial distribution of the Langmuir flow eThe experimental results of radial distribution of Langmuir flow effects in a ring laser gyro are reported in this paper. They show that it is mainly the motion of upper and lower laser level atoms contributes to the ring laser gyro output. Therefore, the discription about the radial distribution of the Langmuir flow effect before is incorrect for laser gyros..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 7, 627 (1998)
An Analytical Solution to the Problem of Laser induced Heating and Melting of Semiconductors
[in Chinese], [in Chinese], and [in Chinese]
An analytical method for treating the problem of the laser heating and melting is developed by suggesting a simple and reasonable temperature profile form. Temperature distribution in a material before melting as well as after melting is given and the movement of the phase interface is also obtained. As an illustrativeAn analytical method for treating the problem of the laser heating and melting is developed by suggesting a simple and reasonable temperature profile form. Temperature distribution in a material before melting as well as after melting is given and the movement of the phase interface is also obtained. As an illustrative example, computations are carried out on a silicon material and the results are in good agreement with those obtained by other authors..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 7, 632 (1998)
The Application of the Ray Tracing to the Diffraction Calculation of an Off axial Laser Beam Transformation System
[in Chinese], and [in Chinese]
This paper uses a space ray tracing method of geometrical optics and light diffraction theory to study a wideband laser beam transformation system which has been applied to the laser heat treatment. The results are compared with the experimental observations.This paper uses a space ray tracing method of geometrical optics and light diffraction theory to study a wideband laser beam transformation system which has been applied to the laser heat treatment. The results are compared with the experimental observations..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 7, 637 (1998)
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