Room temperature Dy:YLF laser operation at 4.34 μm

A Dy:YLF laser operating on the ⁶H_11/2 to ⁶H_13/2 transition at 4.34 μm and using a laser pumping scheme is reported. This pumping scheme is necessitated by the short upper-laser-level lifetime and the small effective stimulated-emission cross section. A suitable laser for this application is the Er:YLF laser operating at 1.73 μm. A simple model that approximates Dy:YLF laser performance well is presented. Results on laser performance, including a determination of the slope efficiency and threshold as a function of the output mirror reflectivity and a correlation of the pulse length with the laser output energy, are reported. Overall laser efficiency is found to be limited primarily by the ratio of the pump wavelength to laser output wavelength and the terminated four-level laser operation     

GaInAsN/GaAs quantum dot laser diodes operating in 1.36 /spl mu/m wavelength range

For the first time, a pseudomorphic GaInAsN DWELL laser with laser emission at 1.36 /spl mu/m and a low transparency current density (206 A/cm/sup 2/) grown by molecular beam epitaxy is reported. The GaInAsN DWELL laser shows a redshift in comparison to an N-free GaInAs DWELL laser of about 90 nm and a transparency current density of 35 A/cm/sup 2/ per single QD layer.     

Re-investigation of optically pumped hydrazine far-infrared laser around 11 /spl mu/m from the 10HP and 10P bands of a pulsed CO/sub 2/ laser: new lines and assignments

A high-peak-power (several hundreds of watts) pulsed CO/sub 2/ laser, recently developed in our laboratory, has been used for exciting optically pumped far-infrared laser transitions of N/sub 2/H/sub 4/. A systematic search for N/sub 2/H/sub 4/ absorption coincidences with 10P and 10HP CO/sub 2/ laser emissions has led to the observation of 27 new far-infrared laser lines, excited by 18 different absorption transitions. All of these new lines have been characterized in wavelength, offset, relative polarization, optimum operation pressure and intensity. Using the LaseRitz program, ten of these lines were assigned, corresponding to five laser systems. For other two laser systems possible J and K quantum numbers of the energy levels involved in the laser transitions were given.     

A vertical monolithic combination of an InGaAsP/InP laser and a heterojunction bipolar transistor

A DH InGaAsP/InP mesa laser and a DH InGaAsP/InP mass-transport laser were successfully put together with an InGaAsP/InP heterojunction bipolar transistor in a vertical configuration. A laser threshold current as low as 17 mA and an output laser power of over 30 mW were achieved. Base injection current-controlled optical bistability and optical switching were demonstrated.     

Complex pulse structure emission from a CO2hollow-cathode laser

A temporal analysis of CO₂ laser pulses generated in a hollow-cathode configuration is presented. A complex laser pulse structure from a single excitation pulse was detected, and the optimum CO₂-N₂ relation for maximum resonant energy transfer was determined. A mechanism responsible for the detected laser structure is suggested     

Trimming phase and birefringence errors in planar lightwave circuits with deep ultraviolet femtosecond laser

A deep ultraviolet femtosecond laser was employed to trim phase and birefringence errors in silica planar lightwave circuits. A permanent refractive index change of /spl sim/3.8/spl times/10/sup -4/ and a birefringence change of 1.0/spl times/10/sup -4/ were induced in hydrogen-free Mach-Zehnder planar waveguide circuits. The ultrafast laser enhances the ultraviolet photosensitivity response in silica waveguides by two orders of magnitude greater than that of a nanosecond 248 nm KrF excimer laser.     

High-power InAlGaAs/GaAs and AlGaAs/GaAs semiconductor laser arrays emitting at 808 nm

Molecular beam epitaxy (MBE) growth, device fabrication, and reliable operation of high-power InAlGaAs/GaAs and GaAlAs/GaAs laser arrays are described. Both InAlGaAs/GaAs and AlGaAs/GaAs laser arrays reached maximum continuous wave output powers of 40 W at room temperature. The external quantum efficiency was 50% and 45% for the InAlGaAs/GaAs and AlGaAs/GaAs laser arrays, respectively. Threshold current density for InAlGaAs/GaAs and AlGaAs/GaAs lasers was 303 A/cm/sup 2/ and 379 A/cm/sup 2/, respectively. While the current of AlGaAs laser arrays went up significantly after 1000 h of operation at a constant power of 40 W, InAlGaAs laser arrays had an increase in the injection current of less than 4% after 3000 h at 40 W.     

Low-threshold (3.2 mA per element) 1.3 μm InGaAsP MQW laserarray on a p-type substrate

A low-threshold 1.3-μm InGaAsP MQW laser array was fabricated on a p-type InP substrate taking compatibility with n/p/n-type laser-driver circuits into account. The laser has a p/n-type current-blocking structure and is made entirely by metal-organic chemical vapor deposition (MOCVD). A 10-channel laser array with a threshold current as low as 3.2±0.2 mA (per element) and a slope efficiency of 0.27±0.01 W/A is obtained     

High-speed photodetection characteristics of a Fabry-Perot laser amplifier under AM and FM formats

A comparison between the photodetection characteristics of an FP laser amplifier under AM and FM formats is reported. A 450 MHz photodetection bandwidth is obtained under the AM format using a Fabry-Perot laser amplifier, with two antireflection coated facets with 10/sup -5/ reflectivity. Using an FP laser amplifier with 10/sup -3/ reflectivity as an FM discriminator/photodetector, a photodetection bandwidth of up to 2.6 GHz was measured.<>     

1.3 /spl mu/m GaAs/GaAsSb quantum well laser grown by solid source molecular beam epitaxy

A highly strained GaAs/GaAs/sub 0.64/Sb/sub 0.36/ single quantum well laser has been grown on GaAs (100) substrate by using solid source molecular beam epitaxy. The uncoated broad-area laser demonstrates 1.292 /spl mu/m pulsed operation with a low threshold current density of 300 A/cm/sup 2/. The spontaneous emission of the laser was also studied. The result reveals that the Auger recombination component dominates the threshold current at high temperature.     

1.47 /spl mu/m Tm/sup 3+/:ZBLAN fibre laser pumped at 1.064 /spl mu/m

A large core area (1257 /spl mu/m/sup 2/) Tm/sup 3+/-doped ZBLAN fibre laser operated at 1.47 /spl mu/m is demonstrated. The pump source is a Nd:YAG laser operated at 1.064 /spl mu/m. A laser output power of 1.56 W continuous wave was obtained for 5.2 W of launched pump power. The slope efficiency with respect to the launched pump power was measured to be 33%.     

XeCl紫外激光与Xe红外激光同时振荡

Ｈｏ／Ｘｅ／Ｈｅ混合气体在横向快放电激发下同时输出ＸｅＣｌ紫外激光和Ｘｅ红外激光．研究了各参量对激光输出的影响，讨论了有关的动力学过程．     

Modes of multi-end-pumped nonplanar ring laser

A novel multi-end-pumped nonplanar ring Nd:YAG laser with two-mirror cavity was demonstrated. A model was developed for attaining all beam loop modes of the laser cavity and calculating the mirror separation of each mode. With single-diode laser pumping, the operations of different modes at 1.064 /spl mu/m were performed and the experimental results are in excellent agreement with the model. Using three laser diodes as the pumping sources led to over threefold increase in output power.     

Measurement of far-infrared laser frequencies from optically pumped CHD/sub 2/OH

A three-laser heterodyne system was used to frequency measure 11 previously observed optically pumped far-infrared (FIR) laser emissions of CHD/sub 2/OH. These newly measured frequencies have fractional uncertainties of /spl plusmn/2/spl times/10/sup -7/ and correspond to laser wavelengths ranging from 47.8 to 238.0 /spl mu/m. The pump laser offset frequency was measured for 15 CHD/sub 2/OH FIR laser emissions.     

A cascade pumped picosecond dye laser system

A picosecond dye laser system producing 4 μJ in a 10 ps pulse is described. This highly stable compact system consists of a nitrogen laser and two cascade pumped dye laser oscillators followed by one amplifier. The Roess-Lin cavity transient technique was applied to compress the input 60 μJ 300 ps N2pulse twice to produce a final output duration of 10 ps. Discrete output wavelengths can be varied by changing the dye laser solution. Spectral and temporal measurements were performed to characterize this laser. A broad spectral emission of ∼ 160 cm^-1was observed, consistent with the observed fine temporal structures of 0.09 ps. A model rate equations calculation was also performed with parameters pertinent to the present laser system. This picosecond laser system should find applications in testing and calibration in the picosecond timescale.     

A large volume copper vapor +HCI--H/sub 2/ laser with a high average power

A copper vapor laser tube with a large volume (15.1 L) has been built for the study of extrapolation in power of the Cu-Ne-HCl-H/sub 2/ laser medium. A high-power (77 kW) all-solid-state high-voltage power supply has been also used for this purpose. Results show an improvement of the optical power after the HCl-H/sub 2/ mixture injection. An optical power of 312 W has been extracted from this laser head in oscillator configuration.     

1.3-μm GaInAsP/InP buried-ridge-structure laser and itsmonolithic integration with photodetector using reactive ion beametching

A 1.3 μm GaInAs/InP BRS laser is monolithically integrated with a photodiode. reactive ion beam etching technique (RIBE) is used for the realization of the laser mesa stripe and for the separation of the laser and the photodetector sections. Influence of the laser-detector gap width, the detector facet inclination, and the laser beam waist on the coupling efficiency between LD and PD are discussed theoretically and experimentally. Coupling efficiency as high as 50 μA/mW is obtained by optimizing the structure. A packaged pigtailed integrated LD-PD is realized, in which the signal emitted from the rear laser facet is detected by the integrated photodiode and used to stabilize the laser output power, through a hybrid feedback circuit, to within 0.1% over 55°C temperature range     

高斜率效率隧道结叠层激光器的研制

隧道结叠层激光器技术具有广泛的应用空间,如高斜率效率、高功率密度、多波长激光器等。采用LP-MOCVD系统生长隧道结材料,CCl4作为p型掺杂源,SiH4作为n型掺杂源,并采用δ掺杂技术,使得n+-GaAs的掺杂浓度大于1×1019/cm3,隧道结的面电阻率小于2×10-4Ω.cm2。设计生长了双叠层、三叠层材料,该材料制作的900nm双叠层激光器在200ns脉宽、20A工作电流下输出功率35W,斜率效率1.8W/A,是单层材料的1.8倍,隧穿结引入的压降约为0.15V;860nm三叠层激光器的斜率效率大于2.7W/A,是单层材料的2.7倍。     

Room temperature operation of type-II GaAsSb/InGaAs quantum welllaser on GaAs substrates

A GaAsSb/InGaAs type-II quantum well laser diode on GaAs substrates was demonstrated for the first time. Threshold current density of 610 A/cm² was obtained from a 1.1 mm-long broad area laser with the emission wavelength of 1.2 μm     

Modelocked Cr/sup 3+/:LiSr/sub 0.8/Ca/sub 0.2/AlF/sub 6/ laser producing 150 fs pulses

Mode-locked operation has been achieved in a CW pumped Cr/sup 3+/:LiSr/sub 0.8/Ca/sub 0.2/AlF/sub 6/ laser. Pulses of 150 fs duration were directly generated from the actively mode-locked laser. A CW krypton laser operating with 1 W in the red was used to pump the 15 mm long crystal.<>