A. N. Imenkov

2.7–3.9 μm InAsSb(P)/InAsSbP low threshold diode lasers

Lasing has been obtained in the wavelength range 2.7–3.9 μm in double heterostructure diode lasers with an active region made of InAs alloys. The devices were grown by liquid‐phase epitaxy. Typical values of threshold current at 80 K were as low as 40 mA and the maximum operating temperature was 180 K. The blue shift of lasing modes was observed with current. This was explained by the increase of the carrier density in the active region above threshold due to intervalence band absorption.

The spectral linewidth of tunable semiconductor InAsSb/InAsSbP lasers emitting at 3.2–3.6 μm (2800–3100 cm−1)

A method was used to measure the width of emission lines of a type of semiconductor laser with composition InAsSb/InAsSbP. This type of laser was manufactured specially for absorption high-resolution spectroscopy of gases absorbing in the 2800–3100 cm−1 region. Parameters used for calculation of spectral emission linewidths were obtained using selected rotation-vibration lines of the gaseous molecules N2O, CH3Cl, and OCS. The estimated spectral emission linewidths varied in the range 10–30 MHz in dependence of the current passing and the type of laser.

Lasers And Avalanche Photodiodes For IR Fiber Optics In The 2-2,5 µm Spectral Range

In present work we report about development of semiconductor lasers and high-speed photodiodes based on GaInSbAs/GaAlSbAs solid solutions for 2.0-2.5 μm spectral range, which operate at the room temperature. Characteristics of.the lasers of several types are described. Among them there are pulsed lasers with output optical power reaching 1 W, cw lasers operating at room temperature at the wavelength of 2.0-2.2 μm, and pulsed lasers for the wavelength up to 2.5 μm. Properties of the developed photodetectors are also presented. There are described high-speed (τ<0.5ns) p-i-n photodiodes with quantum efficiency of 0.6 (without antire-flection coating) and avalanche photodiodes with separated absorbtion and multiplication regions (SAM APD), characterizing by multiplication factor of 20-30 at room temperature.

A tunable single-mode 3.2 μm laser based on an InAsSb/InAsSbP double heterostructure with drive-current tuning range of 10 cm−1

A new type of semi-conductor laser with composition InAsSb/InAsSbP is described. This laser was produced for the absorption spectroscopy of atmospherically important molecules in the 3100 cm(-1) region and tested using a closed-cycle He-cryostat in the temperature range 30-80 K. The optimal characteristics of the laser were found to be a heatsink temperature of 62 K and a drive current range of 50-350 mA. Under these conditions, the laser emits single-mode radiation in an exceptionally large wavenumber range of > 10 cm(-1). To test the laser, several experiments were carried out in which the rovibrational absorption spectra of CH3Cl, NH3, OCS and H2O were measured.

Semiconductor lasers and photodiodes for gas analysis in the spectral range 1.8-2.5 μm

Semiconductor lasers and photodiodes for the 1.8-2.5 micron spectral range are described which can be used in gas analysis systems. The characteristics of pulsed lasers with output optical power reaching 1 W and low-threshold single-mode lasers are presented. The photodiodes have high quantum efficiency (0.6 without antireflection coating) and high speed or response (0.5 ns at reverse bias of several volts).

Optoelectronic LED-photodiode pairs for moisture and gas sensors in the spectral range 1.8-4.8 um

Optoelectronic light-emitting diode-photodiode pairs based on multicomponent GaInAsSb and InAsSbP solid solutions have been researched and developed. Such pairs are able to detect absorption bands of water and gases belonging to the spectral range 1.8 - 4.8 micrometers (H2O, CO, CO2, H2S, N2O, CH4, etc.). Two-wavelength models of a new type of optical moisture meter and a methane meter was fabricated using the developed LEDs and high-efficiency photodiodes.

Suppression of Auger recombination in the diode lasers based on type II InAsSb/InAsSbP and InAs/GaInAsSb heterostructures

Comparative study of threshold current temperature dependence, differential quantum efficiency and light polarization was performed for type I and type II InAsSb/InAsSbP heterostructures as well as for tunneling- injection GaInAsSb/InGaAsSb laser based on this type II broken-gap heterojunction. Experimental evidence of non- radiative Auger-recombination suppression in type II InAsSb/InAsSbP heterolasers with high band-offset ratio (Delta) Ev/(Delta) Ec equals 3.4 was obtained. Reduction of temperature dependence of the threshold current was demonstrated for both kinds of type II lasers. Maximum operation temperature and characteristic temperature T equals 203 K with T0 equals 40 K and T equals 195 K with T0 equals 47 K were achieved for type II InAsSb/InAsSbP and tunneling- injection p-GaInAsSb/n-InGaAsSb lasers, respectively.

3.2 AND 3.8 μm Emission and Lasing in AlGaAsSb/InGaAsSb Double Heterostructures with Asymmetric Band Offset Confinements

We report the first observations of electroluminescence (EL) and lasing in laser structures with high Al-content (x=0.64, Eg=1.474 eV) cladding layers and a narrow-gap InGaAsSb active layer (Eg=0.326 eV at T=77K). The structures are LPE-grown lattice-matched to GaSb substrate. Band energy diagrams of the laser structures had strongly asymmetric band offsets. The heterojunction between high Al-content layer and InGaAsSb narrow-gap active layer has a type II broken-gap alignment at 300K. In this laser structure spontaneous emission was obtained at λ=3.8μm at T=77K and λ=4.25 μm at T=300K. Full width at half maximum (FWHM) of emission band was 34 meV. Emission intensity decreased by a factor of 30 from T=77K to 300K. Lasing with single dominant mode was achieved at λ=3.774 μm (T=80K) in pulsed mode. Threshold current as low as 60 mA and characteristic temperature T 0 =26K were obtained at T=80–120K.

Tunable IR diode lasers based on the A3B5 solid solution for the spectral range 2-4 μm

The structures and electroluminescence characteristics of new two types of single mode A3B5 semiconductor tunable lasers in the 1.8-3.9 micrometers spectral range have been demonstrated. The first type of tunable diode laser based on quaternary solid solutions GaInAsSb and GaAlAsSb lattice matched to GaSb substrate covers 1.8-2.4 micrometers spectral range. Such tunable 1.8-2.4 micrometers lasers have single mode or quasi-single mode operation in the wide temperature range from 1.6 to 300K. The second type of tunable diode laser based on multiple component InPAsSb/InAsSb lattice matched or mismatched to InAs substrate covers 2.8-3.9 micrometers spectral range, which was not available for diode laser spectroscopy until nowadays. Such tunable 2.8-3.9 micrometers lasers have CW single mode operation up to 100K and pulse operation up to 180K. These lasers can be the key devices for diode laser spectroscopy and sensitive detection of pollutants.

Fast tuning of 3.3 μm InAsSb/InAsSbP diode lasers due to nonlinear optical effects

Abstract InAsSb/InAsSbP double heterostructure diode lasers for the spectral range of 3.3 μm grown by liquid phase epitaxy have been investigated. Emission spectra, far-field patterns and wavelength tuning versus current have been studied in the wide current range from threshold value I th up to 3 I th , at the temperature of liquid nitrogen. Controlled by current wavelength tuning in single-mode lasing has been obtained both towards the shorter wavelengths (up to 4.56 cm −1 ) and towards the longer wavelengths (up to 0.9 cm −1 ) at the temperature T =77 K. Comparison of the emission properties of the lasers, driven by different types of current (short pulse current, sawtooth pulse current and in quasi cw regime) showed the same quantum-mechanical nature of current tuning. The theoretical model of this nonlinear optical phenomenon is proposed. The estimated times of current tuning defined mainly by the photon lifetime in the cavity are about 10 −9 –10 −12 s.