Interband cascade lasers are different from any other type of semiconductor laser, both traditional and cascade, because most carriers that produce overall inversion are generated internally, at the semi-metal interface within each stage of the activity area.
Here we show simulations showing that all previous interband cascade laser properties are affected by a significant imbalance in the electron and hole density of the active well.
Our further experiments confirm that the relatively heavy n-
The type doping in the electronic syringe greatly reduces the threshold current and power density relative to all early devices.
At room temperature, the redesigned equipment needs to reduce the input power of nearly two orders of magnitude during continuous operation
Wave mode of quantum cascade laser.
Therefore, interband cascade lasers are the most attractive option for gas sensing and other spectral applications that require low output power and minimum heat dissipation from 3 μm to 6 μm + wavelengths
Electron and hole density and gain are from
The CB and VB structures are uniformly simulated with the Poisson equation at a given additional field. The zone-
Two methods are used to calculate the energy and wave function of the central sub-band
The band of electrons and light
Including hole state and a separate hole state
The belt method of heavy holes.
Using the plane dispersion relationship of typical electron and hole QWs, the simulation speed is accelerated.
The optical gain is the self-employed of the fermilion carrier data in a certain field.
Consistent solver and optical matrix elements calculated from wave functions using standard formalism.
The spiral coefficient is based on the experimental threshold current density and slope efficiency (
Using the internal efficiency determined from the cavity = 76%-
Length study, with little effect on the main results and little change)
To the following functional form: = (+).
Here are the threshold electron and hole density, respectively, obtained by dividing the threshold slice density required to achieve the mode gain equal to the photon loss in the cavity by the normalized thickness 100.
First, the total Helix coefficient = and ratio = are fitted for all samples.
Then, using the above expression and the fixed value determined from the original fit, the spiral coefficient of a single sample is estimated from the threshold current density.
Please note that due to the erroneous overestimation of the threshold carrier concentration, the spiral coefficient we have derived from some previous work is too low.
The ICL wafer is planted inGaSb (100)
The substrate was prepared in the Riber compact 21 t MBE system using the previously described method. The five-
The stage activity area is two 500-nm-thick -GaSb separate-
Constraint layer (SCLs)
And the top and bottom-
The doping layer is 24.
Monthly ainas/23 AlSb superfilm.
The transition area is introduced between the substrate and the bottom cladding, cladding and SCLs, SCLs and active core, and the top cladding and top contact, smoothing the sudden shift of CB offset.
Production Using contact exposure and wet chemical etching 150-μm-
Wide ridges of pulse properties.
The etching continues to proceed to the GaSb cl below the active area and uses a mask with deliberately transverse ripples on the side walls of the ridge to defeat the parasitic laser pattern.
Narrow ridges with different widths were created by exposure and reaction
Ion etching using Cl-
The induction coupled plasma process stopped in the bottom GaSb cl region.
Then washed the ridge with phosphateacid-
Based on wet etching to minimize damage caused by dry etching. A 200-nm-
Thick SiN layers are deposited by plasma
Enhanced chemical vapor deposition and top
Etching back to contact window with SF
Coupled Plasma based on induction.
Next, the SiO at 100 nm is splashed down to block the occasional fine holes in sin.
Then plated the ridge with 5 μm gold.
Different cavity lengths were cut and a small surface coating was applied on some devices.
HR coating by 46-nm-
100 thick AlO andnm-Thick Au layer
AR coating made of 524-nm-thick AlO (/4)layer.
These devices are installed on the extension side of the copper radiator connected to the thermoelectric cooler.
CW mode or pulse representation of the device using a repetition frequency of 3 kHz and a pulse width of 200 ns.
Several devices on each wafer were tested to verify that the reported threshold represents a specific wafer.
For devices from a given wafer, the repeatability of the threshold current density is usually within 5%.