A new tunable source of infrared radiation based on intersubband electron Raman scattering in semiconductor quantum wells is theoretically studied. The structure consisting of three levels in two coupled GaAs/AlGaAs quantum wells is optimized for a maximum Raman gain at zero bias. Raman gain as large as 400/cm can be achieved according to our calculations. Lasing wavelengths are tuned by applying external dc bias field along the growth direction. An infrared tuning range of 8 to 12 micrometers , with moderate Raman gain, is predicted as the electric field is varied from -40 to 40 kV/cm.

Because of the absence of polar optical scattering, the lifetime difference of the upper and lower lasing levels, to which population inversion and laser gain are proportional, is an order of magnitude larger in silicon-based structures than in the III-Vs. Further enhancements are due to phonon confinement. For lasing wavelengths 10 micrometers and longer, Ge_xSi_1-x/Si is used. For operation at near infrared wavelengths, high barrier materials are needed. To avoid large operating voltages, designs are considered which rely on parallel rather than sequential operation.

In this paper, the dynamic emission spectra of high- frequency pulsed laser diodes have been studied in order to investigate the spectral stability of each laser pulse and to examine the influence of the HF-pulsed laser diode's mode hopping and frequency jitter on the interferential fringe system in LDA applications. It has been shown that, by choosing appropriate operating points, a HF-pulsed laser diode can be operated to have optical characteristics such as mono-mode emission, a stable wavelength from pulse to pulse and high optical output peak power. The selection of optimal operating points for LDA applications may be not required if semiconductor lasers with periodically structured laser resonators of for example the distributed- feedback type or the distributed-Bragg-reflector are used.

In this paper AlInGaAs/AlGaAs strained quantum well broad- stripe lasers with proton insulating grown by metalorganic chemical vapor deposition, lasing at 808 nm are presented. Electrical and optical characteristics and reliability of this lasers were investigated and compared with (Al)GaAs/ALGaAs quantum well lasers manufactured by the same technology. It was shown that diode lasers based on quaternary material system presents the advantage over AlGaAs diode lasers in operating efficiency and reliability due to In contained in active layer, and consequently, hardening of the crystal lattice. Thus, laser diodes with lifetime more than 10⁴ hours at operation power 0.5 Watt in cw multimode regime were manufactured.

We have assessed the structural perfection of as-fabricated light emitting devices using cross-sectional transmission electron microscopy and high resolution transmission electron microscopy. We have used the electron beam induced current and cathodoluminescence techniques to evaluate the electrical activity of the structural defects. Results indicate that the density of threading dislocations in the device structure is about 10¹⁰ cm^-2, and they are of edge character. We argue that this high density is a consequence of the coalescence of the AlN islands that form on the SiC substrates. We also discuss the replication behavior of the threading dislocations during subsequency growth. Both the electron beam induced current and cathodoluminescence images show non-radiative recombination regions. We attribute them to the presence of the threading dislocations.

Lattice-matched In_0.53Ga_0.47As/InP quantum well (QW) structures are of considerable interest in photonic application since they enabled device operation in the 1.3micrometers to 1.55micrometers wavelength range which is of importance for optical communication systems. The process of interdiffusion modifies the as-grown square QW to a graded QW which alter the subband structure and optical properties of the QW. Thus it provides a useful tool for bandstructure engineering. The interdiffusion process of InGaAs/InP QW provides more degrees of freedom than AlGaAs/GaAs QW system since interdiffusion can occur for group-III, group-V, and groups III plus V together. These are determined by the temperature and chemical environment used during annealing of the QW structure. The effect of interdiffusion on the laser performances of InGaAs/InP QWs is also studied based on these different types of diffusion processes. It is found that the operating wavelength shows both a red shift and a blue shift depending on the types of diffusion process. It is also found that group-III interdiffusion gives the best performance of InGaAs/InP QW laser when comparing to the other tow types of interdiffusion in terms of a smaller threshold carrier density.

The carrier-induced effects in the change of refractive index on the GaAs/Al_WGa_1-W as square quantum well (SqQw) and diffused quantum well (DFQW) was investigated. Band-filling, bandgap shrinkage, and free- carrier absorption were included. Carrier concentrations from 10¹⁶ to 10¹⁸ cm^-3 were considered. The energy levels and their associated wavefunctions in the SqQW or DFQW structures are calculated by solving both the Schroedinger and the Poisson equations self-consistently. It is followed by the absorption change, which is defined as the difference between the absorption coefficient with carrier injection in QW and that without carrier injection. The refractive index change can be obtained by applying Kramers-Kronig Transformation. These results obtained are useful in the design of devices, such as lasers, optical phase, modulators and switches. Thus, it is important to know the carrier-induced energy shift in GaAs/Al_WGa$_1-W) as quantum well structures.

The in-orbit experiments of OICETS (optical inter-orbit communications engineering test satellite) are categorized into 4 types as follows: 1) the performance verification of optical devices (laser diode, APD, CCD, QD) in space, 2) experiment for acquisition, tracking and pointing of an optical link, 3) optical communications experiment with ARTEMIS, and 4) optical link experiment between OICETS and an optical ground station. The experiment plan has been detailed taking account of the conditions of the optical terminals, the satellite bus, the operation for control, and the orbit location. The design of the ground system for the experiment las also proceeded in compliance with the requirements from the experiment plan. The detailed experiment plan is reported in this paper, together with the design of laser utilizing communications equipment.

The gain coupled gratings are analyzed by the extension of a well-known coupled mode theory, first developed by Streifer et al. in 1977. We present a new matrix method that takes into account the polarization nature of the non-dominant modes, that has been ignored in the previous theories. Our method can analyze any grating irrespective of its shape, its order and its type. It is based on slicing the grating layer such that in each layer, the equivalent waveguide refractive index and excitation can be considered as constants. We obtain different coupled wave equations, as we applied this method to pure gain coupled DFB lasers. It is worth noting that our theory is presented in the under threshold regime.

The superiority of gain or loss-coupled DFB lasers over the index coupled ones are evident in many respects. However the fabrication of first order gain or loss coupled gratings involves many difficulties. Therefore we are practically restricted to employing higher order gain or loss-coupled gratings. One of the main disadvantages of higher order gratings is radiation losses. To take into account both the effects of higher order modes on coupling and losses in linear regime, we apply a well-known coupled wave analysis due to Striefer et al. In 1977 to loss coupled DFB lasers. This theory using the first order perturbation analysis is suitable for analyzing shallow gratings. It leads to a pair of coupled wave equations, where coefficients indicate all the possible coupling losses.

The effects of the external feedback on the noise properties of semiconductor laser are studied based on the feedback- induced-dynamics. The steady-state analysis shows that the oscillation mode can be determined from the phase condition in the way that the mode with the maximum stability factor is selected rather than the mode with the minimum excess gain. Both the phase and intensity noises are investigated by including Langevin noise sources in the rate equations. As the feedback level increases, the linewidth and the relative intensity noise level exhibit three different stages of variations leading to coherence collapse state where the corresponding dynamics is fully chaotic. A double- external-cavity model is proposed as an example to stabilize the feedback-induced chaos. Numerical results indicate that, for certain parameter range, the original chaos can be stabilized to periodic oscillations or fixed states and consequently, the linewidth and the RIN level in the low- frequency range can be reduced to the extent of the solitary laser.

The dependence of spontaneous carrier lifetime (tau) _s suggests new experiments for the determination of microscopic parameters of the active region material. Cavity geometry's are time evolving structures due to the high non- linearities typical of the elementary processes involved. A computational approach basically different from the differential equation one, is being developed. The results obtained by this approach are compared with the analytical and the experimental ones, thus leading to the possible characterization of devices just at the wafer level. Finally complementary information are extracted from relaxation oscillations.

High power laser diodes have been continuously gaining more practical applications. In the majority of these applications, device performance is a determining factor. However, device reliability determines whether a laser diode can be successfully introduced in a commercial product. We review some device reliability problems and their solutions found through customer experience while supplying packaged high power AlGaAs/GaAs quantum well laser diodes, utilized in medical, high resolution printers. The reliability problems were related to either photo-induced chemical reactions on the output facet leading to visible optical damage or the propensity of the material to rapidly develop dark line defects. To improve the reliability of high power laser diodes, we have performed numerous aging studies, followed by detailed failure mode analysis. Both hermetically packaged devices and devices exposed to air ambient were evaluated. The devices whose parameters deteriorated during aging were examined with optical microscopy, infrared microscopy, scanning electron microscopy, Auger spectroscopy, residual gas analysis and also electron beam induced current. We report the results of the failure mode analysis and suggest solutions to eliminate failures of high power laser diodes.

This paper reviews the development of semiconductor lasers, especially the breakthrough on quantum well lasers in China. Regarding on the super thin material growth, the developing history of Molecular beam epitaxy and metalorganic chemical vapor deposition are briefly introduced. Taking some kinds of lasers as examples, the characteristics of long wavelength MQW F-P LD and MQW DFB LD, 808nm high power lasers and visible lasers are also demonstrated. The low dimension lasers including quantum wire and quantum dot are under way.

The far-field control of vertical-cavity surface-emitting lasers (VCSELs) has been studied experimentally and theoretically. The experimental results show that the window and the gain-guided area radiuses of VCSELs strongly influence laser far-field distributions and beam characteristics; for VCSELs with small window radius w equals 2.5 micrometers , only one dominant lobe has been observed in the far-field profiles, even though injected current was increased up to 2 I_th; and the smaller the ratio of the window radius to the gain-guided area radius, the larger is the far-field divergence. To understand the experimental results, we have also performed a calculation using a method of finding self-consistent solutions for the carrier diffusion and the optical field equations. The calculated results are in good agreement with those of the experiments.

Experiments on mode selection and active mode-locking in laser diodes with an external Fabry-Perot (FP) interferometer are reported for the first time. The static and dynamic single internal-mode operation have been realized successfully by using a PZT to adjust the interval of the FP interferometer. The nearly transform-limited Gaussian pulses with the repetition rate of 656MHz, the pulsewidth of 13ps have been obtained by active mode- locking.

According to the transmission theory for elliptical Gaussian beam, two transcendental equations which about the maximum range and the maximum threshold beam spot range are derived. These two equations are solved with iteration. Two conclusions are obtained.

This paper introduces, for the first time to the authors' knowledge, a novel use of laser diode (LD) in forming a sensor to measure the optical refractive index or concentration of liquids. The way described is also appropriate for precise displacement measurement, location and collimation. Special design by combining a LD and a position sensitive device enables this sensor to work for on-line test and remote control. This sensor is significantly much simpler in structure than those refractometers based on the optical principle of total reflection, which usually need complicated optical and/or electrical systems for achromatization, beam scanning or observation like Abbe Refractometers or those refractometers with CCD. With this sensor, we get a resolution power of refractive index of 0.0001 and a dynamic index range of 1.3330 up to 1.4247, corresponding to a range of sugar concentration in aqueous solution of about 0-52 percent at 20 degrees C. A better result is expectable.

We have reported for the first time on visible photoluminescence (PL) in crystallized a-Si:H/aSiN_x:H multilayers structure by CW Ar ion laser annealing treatments. In this paper we present new results on visible PL and electroluminescence (EL) from crystallized a:SiH and its based multilayers by using KrF excimer pulse laser irradiating treatments. Strong and stable PL and EL have been observed by naked eye in both laser irradiated a-Si:H and a-Si:H/aSiN_x:H multilayers samples at room temperature. The EL peak of crystallized a-Si:H/a-SiN_x:H multilayers is blue shifted from 1.79 eV to 2.00 eV with narrowing the well layer thickness from 4 nm to 2 nm which suggests the origin of the light emission should be related to the quantum size effect.

Hydrogenated amorphous silicon carbide alloys were produced by using organic carbon source, xylene, instead of generally used methane. It was found that the optical band gap of present samples is significantly increased and reaches as high as 3.1eV with increasing the xylene gas fraction to 80 percent. The film configuration was also investigated and it was shown that there exist a lot of aromatic rings in the film network. An intense blue light emission has been observed from the present samples. The luminescence wavelength is peaked in the range of 490nm to 610nm, the origin of the light emission is briefly discussed in this paper.

The effects of the thickness of the oxidized layer, reaction temperature and carrier gas flow on the oxidation rate of Al_xGa_1-xAs-AlAs-GaAs heterostructures are presented. The electrically-pumped GaAs/AlGaAs vertical cavity surface emitting laser 2D arrays fabricated by selective etching and selective oxidation are described. The square current flow aperture of 4 X 4 micrometers ² are formed by the buried oxidized AlAs layers formed on both top and bottom distributed Bragg reflectors adjacent active region. The serious resistance of the devices are 60 to 80 (Omega) . The continuous-wave threshold current as low as 3.8mA is obtained at room temperature. The devices show the maximum output power over 1mW. Their angles of divergence are less than 7.8 degrees and the pulse rise times are less than 100ps in the high speed pulse response measurements. The 2 X 3 2D arrays are obtained. The thresholds of devices in the array are within 6 +/- 0.5 mA.

A kind of novel complex-coupled gratings by modulated distribution of injection current (MDIC) along the propagating direction of modes of lasers, was designed and analyzed theoretically. The impacts of two practical cases on MDIC gratings were discussed, which indicated the MDIC gratings could function effectively. Some necessary parameters were calculated and were put into practice in actual device process successfully and proved to be reliable. Furthermore, MDIC DFB lasers, based on the active layer with five quantum wells, were fabricated firstly by MOCVD and LPE. The devices began to lase continually about 30mA. The stable single longitudinal mode wavelength is just at 1.3151 micrometers , located in the zero dispersion window of optical fibers. There is no appearance of stop band in the quasi-threshold spectrum. As a consequence, high side mode suppression ratio of more than 30dB and high single longitudinal mode yield have been realized by using this MDIC complex-coupled structure.

In this paper, the temperature dependence of upconversion luminescence from Pr,Er,Yb codoped ZBLAN glass pumped by 960nm laser diode was studied. The temperature dependencies of upconversion luminescence for Pr³⁺ and Er³⁺ in ZBLAN glass were compared. The results showed that the temperature dependence of upconversion luminescence from Pr⁺ is different to that from Er⁺ in ZBLAN glass.

A new algorithm, SAIO, is proposed to design the binary diffractive optical elements. It is very excellent for the design of two dimension optical transformation system. In this paper, we use SAIO algorithm to design and fabricate the 8-phase levels diffractive elements for converting the semiconductor diode laser elliptically Gaussian beam into circular uniform beam. The experimental results indicate that the output beam profile is consistent with the theoretical calculation. The measured energy transformation efficiency is about 88 percent.

In this letter, we report the MBE growth of GRIN-SCH ALGaAs single quantum well lasers. In order to obtain high quality laser materials, superlattice among GaAs buffer and n-AlGaAs cladding layer was incorporated. Reduced Be dopant concentration in the p-AlGaAs cladding layer near the GRIN region was adopted, which is believed to be benefit to the control of p-n junction places and reduction of the oxygen incorporation. High power broad-area lasers were fabricated. The typical threshold current density is 300A/cm² and the minimum threshold current density is 220A/cm² for the 500 micrometers cavity length lasers. High slope efficiency of 1.3W/A for 1000 micrometers cavity length lasers was obtained, recorded CW output power at room temperature has reached 2.3W. The measured characteristics temperature T(subscript 0$. is as high as 185K.

In this article we will generalize and analyze different self-aligned techniques for different stripe lasers, for example: ridge waveguide lasers, buried heterostructure stripe lasers, mushroom-stripe lasers, etc. Finally, a novel self-aligned processing technique for fabricating buried mushroom-stripe lasers is proposed and it has been utilized successfully in fabricating bent waveguide mushroom-stripe MQW DFB lasers.

We report on the design and fabrication of 980nm InGaAs/AlGaAs double quantum well lasers with low vertical beam divergence. The specially designed structure, which characterized by two low refractive index layers inserted between the cladding and waveguide layers, was theoretically studied using the shooting method and systematic calculation. Results for the beam divergence and far-field distribution are given, and the physical concepts are discussed. Experimental investigation by molecular beam epitaxy was performed. For the fabricated as-cleaved 3micrometers - wide ridge waveguide structure lasers having a cavity length of 800micrometers , a threshold current of 30mA and an external quantum efficiency of 0.8mW/mA were achieved. The measured far field pattern has a vertical divergence of 21 degrees and a horizontal divergence of 8 degrees.

Based on the equivalent resistance and finite element method, the current distribution in active region is analyzed with current injection from ring electrode. To improve the injection efficiency and reduce the resistance of p-type DBR, we design reverse mesa structure and achieved low threshold current InGaAs vertical cavity surface emitting laser operation. In situ thickness monitoring and controlling in MBE growth is also studied.

The influence of rapid thermal annealing (RTA) on the doping profile and the structure of quantum well LD have been investigated by means of Hall measurement, Auger Electron Spectroscopy, and Secondary Ion Mass Spectroscopy methods after certain RTA. It has been discovered that high resistivity layer was formed at the ohmic contact layer after RTA. However, the structure of quantum well LD is not influenced by RTA.

A new type of strained InGaAs/GaAs ridge quantum wires (QWRs) structure has been proposed and fabricated firstly by MBE growth on patterned substrate. High resolution scanning electron microscope studies show that these ridge structures were formed with top and side faces. The photoluminescence measurements indicated that the lateral quantum confinement effects of the ridge-QWRs caused a blue-shift of the quantum confined energy, which agrees with the approximate calculations for the strained-ridge-QWR structure using Kronig-Penney model. This strained-ridge-QWRs consists of three aspects of lateral confinement effects. Firstly the thickness of ridge quantum wells on the ridge top is larger than that on the side surfaces; secondly the Indium concentrations on the ridge-top region is higher than that on the side region; thirdly the strain effects lead to a larger energy gaps in side plane than that in the ridge top. The above three factors were incorporated to enhance the confinement effects on the lateral motion of carriers in strained ridge QWRs.

The structures of InGaAs/GaAs strained QW vertical cavity suurface-emitting lasers with low threshold current have been grown on tilted substrate by a modificatoy MBE system. The VCSEL structure contains 23.5 pairs n-type DBR , a strained InGaAs/GaAs 3QW active region ,and 20.5 pairs p-type DBR. The emission wavelength of InxGaixAs IGaAs QW lasers as a function of indium contents (x) and QW width has been studied theoretically and experimentally. The experimental results compared with theoretical calcuulation were in good agreement. The device measurements showed that room temperature CW operation of VCSEL has been achieved with the threshold current as low as 0.7 mA at 9430 A wavelength, and quantum efficiency above 12%.

The stimulated emission with multimode structure from the n equals 1 heavy exciton was observed in a Zn_0.8Cd_0.2Se-ZnSe strained layer superlattice at 77K. It is found that the different modes have different half widths of the time delay curves, depending on the different threshold for each model. Therefore, the threshold relation can be qualitatively obtained in terms of the half width of the time delay curve.

We describe the fabrication and operation of vertical cavity surface emitting lasers (VCSELs) by pulsed optical pumping. The VCSELs structure is a ZnSe-ZnS MQWs with a Fabry-Perot cavity. The stimulated emission in ZnSe-ZnS MQWs VCSELs is observed at thresholds of 3.6MW/cm² with the wavelength near 440nm at 77K. On the basis of the absorption and photoluminescence spectra in the ZnSe-ZnS MQWs, we attribute the major physics mechanism for the stimulated emission of ZnSe-ZnS MQWs VCSELs to exciton and exciton interactions.

A modified liquid phase epitaxy method was used to grow InGaAsP/GaAs SCH SQW multilayer structures for the diode lasers emitting at 0.81 micrometers . In order to prevent the phosphorus evaporation from source melts, the epitaxy process was carried out at the temperature as low as 750 degrees C. The lowest threshold current density I_th was 300A/cm², the very high value of the total differential quantum efficiency obtained from long-cavity diodes exceeded 80 percent, the highest CW optical power obtained without any coatings was 2.1W.

A new wafer bonding-etching technique has been developed successfully for micro-disk laser fabrication. Pillar-free micro-disk lasers have been realized. The micro-disk is placed on low refractive index material such as SiO₂ and surrounded by SiO₂ and air. The pillar-free micro-disk laser shows more solid than the pillar-supported micro-disk lasers. It has similar threshold pump power compared with the pillar-supported micro-disk lasers.

The operating characteristics of Al-free InGaAsP/GaAs separate confinement heterostructure single quantum well high power laser grown by low-pressure metalorganic chemical vapor deposition are reported. The internal differential quantum efficiency (eta) _i is closed 98 percent. The external differential quantum efficiency (eta) _d of 75 percent and characteristics temperature T_o of 146 degrees C are achieved, CW total output power both facets of 2.6 W single quantum well laser with 100 micrometers width, 1.1 mm cavity length is obtained. Threshold current density J_th, reciprocal differential quantum efficiency l/(eta) _d, emission wavelength (lambda) and characteristics temperature T_o as function of laser cavity length L respectively have been measured and researched. Dependence of J_th (T), (lambda) (T), and (eta) _d (T) respectively on temperature T have been given and explained.

A short coherence length of a laser diode (LD) is required in coherent resolved interferometers. The coherence length of a LD can be reduced by modulating the source with a high frequency signal, which is superposed on the driving current for the LD. A 980nm laser diode in this paper is modulated with a frequency 40MHz and modulation depth 0.5, where its coherence length is compressed 20 times. The first side-band peak in the coherence function is reduced by 10dB, but it is hard to suppress them completely.

Traveling-wave semiconductor optical amplifier with self- phase modulation can be used to compensate for the laser chirp and optical fiber dispersion. Steep pulse edges of the initial laser output pulses lead to incomplete phase compensation and the compensated pulse distortion after a fiber transmission because the nonlinear chirp is added to the compensated pulses. Satisfactory operation of phase compensation, with small transmitted pulse distortion, is possible if the SOA is operated under optimum saturation level.

Recently there ar some reports on the AlInGaAs/AlGaAs material system with emission wavelength in the range of 800-890nm. The AlInGaAs/AlGaAs strained quantum well lasers are usually grown by metal-organic chemical vapor deposition and there are few of them that have been grown by solid- source molecular beam epitaxy (MBE). In this paper we report the characteristics of AlInGaAs/AlGaAs strained quantum well materials and lasers grown by MBE. A typical 10K photoluminescence spectrum with FWHM value of 10 meV is comparable with that of GaAs/AlGaAs quantum well materials. InAlGaAs/AlGaAs strained quantum well lasers with a emission wavelength of 810nm were fabricated, the threshold current density is 375 A/cm² for broad-area lasers, and it decreases to 290 A/cm² when the cavity length extend to 1600 micrometers an external differential quantum efficiency of 0.92 W/A and narrow perpendicular beam divergence of 32 degrees are demonstrated for the uncoated lasers with cavity length of 800 micrometers .

Using the character that the emitting optical frequency of the laser diode is controlled by the injected current, the ability of eliminating environmental disturbance of the sinusoidal modulation laser diode active interferometer will be raised by more than one hundred times through putting the disturbed interference signal produced by the environment into the interferometer. When vibrating frequency of objects is different from that of the sinusoidol modulation, 'beat- frequency' will be produced in the interfere signal, which can be analyzed to get the vibrating frequency of objects. This paper described the operation principle and theoretical delusion of the 'beat-frequency' method.

A new design to lock frequency in directly doubling blue lasers is presented. We employ external gratin placed on the PZT tube to feedback lock the frequency of laser diode. The spacial distribution of LD is reduced 2.1 times and spectral distribution of LD is also compressed. Stability testing of blue laser is reported too.

In this report, InGaAs/InGaAsP separated confinement strained-layer multiple-quantum-well laser structures for 1.48micrometers emission wavelength have been grown by LP-MOVPE. The lasing characteristics of the dependence of threshold current densities on the inverse of cavity length and the dependence of threshold current on the cavity length have been studied with room temperature pulse operated broad-area lasers. To reduce the threshold current, the room temperature CW H⁺ ion implantation stripe lasers with varies widths have been fabricated. The stripe width dependence of threshold current for a set of these devices have also been investigated. Besides, to obtain a high output power from the front facet, we have studied the design of the facet reflective.

The progress in 1.3 micrometers wavelength InGaAsP/InP lasers for optic fiber communication and subscriber loop applications is reviewed. By using LP-MOVPE/LPE epitaxy techniques, the performance of commercial optical devices is considerably improved. The bandwidth of the 1.3 micrometers uncooled MQW-LD module could be high to 1.6GHz, threshold current I_th < 15mA, maximum fiber output power P_f >= 20mW while uniformity, reproducible, high yield are achieved. Further by growing active layer with compressive strained structure the lowest threshold current I_th equals 3.8mA was achieved with high reflection coating and the temperature performance of the SL-MQW-LD has been greatly improved, the change of slop efficiency at 25 degrees C and 85 degrees C is less than 1 dB. Using the holographic technique a high power 1.31 micrometers InGaAsP/InP multiquantum well distributed feedback laser has also been developed. The fiber output power of butterfly packaged module with optic isolator P_f > 10mW, threshold current I_th < 18mA, slop efficiency E_s > 22 percent and side mode suppression ratio SMSR > 40dB. The composite triple beat CTB < -66dBc and the composite second order CSO < -56dBc by test frequencies equals 55.25 to approximately 289.25MHz with 40 NCTA channels, the carrier to noise ration CNR > 50 dB and the relative intensity noise RIN < -160dB/Hz.

According to the transmission theory for elliptical Gaussian beam and the boundary condition of threshold beam spot, the relationship equations between the major and micro half (axises of ellipse with range), which determine the space shape of threshold beam spot, are derived. Extinction parameter and extinction function are introduced properly, which makes the maximum half-axis equation of threshold beam spot in this article is more reasonable than that in ADA 102276.

Single quantum well AlGaAs/GaAs semiconductor lasers which have superlattice buffer layer have been fabricated by MBE. The experimental results how that the superlattice buffer layer can effectively bury the substrate defects and well interface can be achieved. The lasers can work continuously at room temperature, the operating wavelength is 780 +/- 2 nm and the lowest threshold current at room temperature is 30 mA, the output power with uncoated facets is greater than 20mW.

Due to the potential barriers in the heterointerfaces of quarter wavelength stack layers of the distribute Bragg reflector (DBR) in vertical cavity surface emitting lasers, P-DBR has a very large series resistance. The paper reported a method of reducing this series resistance by Zn diffusion. By this way, we have achieved continue wave vertical cavity surface emitting lasers.

The purity of GaAs grown by MBE was improved significantly when the MBE system was modified. The AlGaAs/GaAs quantum well heterostructures for mid-infrared detectors and two color infrared detector and InGaAs/GaAs quantum well heterostructure for vertical cavity surface emitting laser were grown successfully.

This paper presents new results obtained recently in studies of separate confinement structure InGaAsP/lasers. Using Russia's technology, the InGaAsP/GaAs lasers based on QW structure can be produced y a short-time liquid phase epitaxy employing a modified sliding boat technique. The interface abruptness in the InGaAsP/GaAs lasers can be made comparable to the lattice constant. Using 100 GaAs substrates, InGaAsP/GaAs SCH SQW lasers were fabricated and the following values of the main parameters were obtained: lasing wavelength (lambda) equals 808 micrometers , threshold current density J_th equals 100A/cm², and power conversion efficiency N $eq 56 percent at a CW power of 1W for a laser with a stripe width W equals 100micrometers .

Hg_1-xCd_xTe infrared photodetectors with high CdTe mole fraction of x equals 0.50-0.65 were studied by deep level transient spectroscopy and photocapacitance measurement. Two electron traps, E₁ and E₂, were observed in all samples. The thermal emission activation energies and capture barriers of the two electron traps were determined by DLTS and were observed to depend on CdTe mole fraction x. In the sample with CdTe mole fraction of x equals 0.60, the binding energies of E₁ and E₂ are about 0.30 and 0.45 eV, respectively. At nearly the same values of the binding energies, the capacitance changes also appeared in the steady-state photocapacitance spectra of the samples, which indicates the small lattice relaxation of the two electron traps. The physical origins of the electron traps are discussed.

2.5 micrometers wide ridge waveguide laser emitting wavelength 980nm were described. The epitaxial structure was a step- index separate-confinement strained single quantum well heterostructure which was grown by MOCVD. About 150mW output power are achieved for 600 micrometers long laser.

In this paper, the logical function of CCTS transistor bistable laser is theoretically analyzed and experimentally studied from the non-line equation, and its quantitative and quality analysis results has been drawn, at the same time. It has been found that when the laser output high state and the injection electrical is continually increased, there occurs another bistable phenomenon. It is confirmed by studies that it is the self-electro-optic effect of quantum well PIN detector. This two bistable occurs self-lock phenomenon at special temperature, and a double switch circuit model device is set up.

In this paper we present a theoretical analysis on the effects of increasing absorption and amplification of light in the semiconductor optical bistable system, though the results may be available to a class of excitonic OBS. The Heisenberg equations for the motion of excitons and lightfield modes are deduced. By theoretical analyzing and numerical computing, we study the conditions and characteristics of bistability and lasing. The results how that the system displays different bistabilities depending on the relative intensities of varied interactions, a novel hysteresis loop appears even in the lasing region, thought eh increasing absorption restricts the lasing effect.

We have simulated fiber communication systems with the semiconductor micro-cavity lasers as light transmitters using rate equations. When the spontaneous emission factor of micro-cavity equals 0.1 and the lasers are modulated by 10 Gbit/s numerical codes, we have obtained both the received eye diagram after they transmit 60 kilometers and the relations of the unit area of the eye diagram with the transmission distance. It will provide theoretical value for the application of the micro-cavity lasers in optical communication.