Trumpf produces high tech laser machines with special concentration on the production and the medical sector. Trumpf produces laser technology machines which could be customized as well. It gives you the competitive power edge emitting diode which could be transformed into a sustainable competitive advantage. The key element involved in the production of these machines is the laser diode. A laser diode is nothing but a type of laser. In a laser diode the medium that is active is called a semiconductor. This is similar to the case of a LED. One of the most common types of laser diode is made with the help of a p-n junction which is powered with the help of the electric current that is injected into it. They are also famously referred as the injection laser diodes.
The operation of laser diode
- By doping a very thin layer on top of a crystal wafer a laser diode is formed.
- This leads to the formation of the p-type region as well as the n-type region, one on top of the other which is referred as the p-n junction which is famously called as the diode.
- The laser diodes are nothing but just another subgroup of the larger p-n junction diodes.
- When electrical bias is forwarded into the laser diodes it leads to the formations of the two types of laser diode carriers of the charge which are named as the holes and the electrons.
- These charge carriers are inserted from the either sides of the p-n junction aiming the region of depletion. The one that is inserted from the p side is called as the hole and the one for the n side is called as the electrons.
- Optical pumping is considered to be the other method for powering up the laser diodes.
- If there is an electron and a hole that is present in the same region it tends to combine together and results in spontaneous emission. This resulting act is necessary for the purpose of giving the laser diode the below lasing threshold which leads to the laser oscillation which is high power laser.
- The major difference between the different laser diodes depends majorly on how the semiconductor laser layers are used.
The types of the laser diodes
All of the major machineries that are produced in Trumpf majorly fall under the following types of laser diodes.
1. Double heterostructure lasers
When it comes to this type of the laser there are two bandgap layers with high power between which a low bandgap material is placed. The junction between the different layers of the bandgap is called as the heterostructure. This is why it is referred as the double heterostructure laser. The major advantage of this laser is that the active region is controlled in the middle layer. The active region is the region in which the free holes and electron exists simultaneously. There are many pairs of such holes and the electrons all of which contribute vastly to the amplification. Apart from this, from the heterojunction layer light is reflected, thereby confining the light to the region of amplification.
2. Quantum well lasers
This is similar to that of the previous model except for the fact that the middle layer is very thin and this layer acts as the quantum well. This directly refers to the fact that there would a vertical variation in the wavefunction of the electrons leading to the quantized component of the energy. These types of laser are considered to be more efficient than that of the bulk lasers because of the fact that there is an abrupt edge that leads to the concentration of the electrons in the energy states that contributes to the powerful laser action.
When there is a presence of more than one layer of the quantum well, it is called multiple layered quantum well. When there quantum well are multiple then it tends to increase the region of gain with the help of the mode called as the optical waveguide. If you want to further increase the efficiency of this model then it could be done by reducing the quantum well layers into quantum wires. This could also be done by reducing the quantum well layers into a sea that is filled with quantum dots.
3. Quantum cascade lasers
The difference between the quantum well energy layers is taken for the purpose of transition of laser instead of the bandgap like in the other cases. This helps in the longer wavelength of the laser beam. This can be done just with a little tuning to the thickness of the layers which are the heterojunction layers. When it comes of the quantum well laser the major problem is that the thin layer is way too thin and puny therefore it doesn’t effectively confine light. This design is named as the separate confinement heterostructure.
4. Distributed feedback lasers
They are considered to be the most commonly found laser that belongs to the transmitter category and they are majorly found in the DWDM systems. Close to the p-n junction a diffraction grating technique is etched with the main purpose of stabilizing the wavelength. This main function of the grating is to act as the optical filter which leads to feedback of just a single wavelength to the gain region and to the laser. At least one of the facets in this type of laser is anti-reflection coated therefore leading to the stable wavelength.
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