Distributed Bragg reflector, DBR

To demonstrate the method an example of a slow-wave optical structure is modelled. Such structures consist of a cascade of directly coupled optical resonators in order to enhance the nonlinear effects. The structure used here was recently defined within Working Group 2 of the European Action COST Pll (http //w3.uniromal.it/energetica/slow waves.doc). One period of the structure consists of one-dimensional Fabry-Perot cavity placed between two distributed Bragg reflectors (DBR) and can be described by the sequence... 

Figure 10-12. Left hand side Structure of a PPV microcavity. A thin film of the conjugated polymer is deposited on top of a highly reflective distributed Bragg reflector (DBR). The second mirror is then fabricated by evaporation of a silver layer. Right hand side Emission spectra of the microcavity at excitation energies of 0.05 pJ (dashed hne) and 1.1 pJ (solid line), respectively. Laser pulses of duration 200-300 ps and a wavelength of 355 nm were used for optical excitation (according to Ref. [39]).

Modem design of efficient surface emitting semiconductor lasers implies monolithic solid state stmctures with an active layer and periodic multilayer stacks comprising Distributed Bragg Reflectors (DBR). The latter provides reflection band at the emission wavelength due to multiple reflection/interference in a complex medium with periodically graded refraction index of the layers [1], The larger is the refraction index difference A n = U/ - between a couple of materials chosen to... 

Distributed Bragg reflector (DBR) and distributed feedback (DFB) fiber lasers have relatively short cavities, e.g., 10 cm or less, facilitated by the use of heavily doped-fiber amplifiers. The aim is to provide increased cavity mode... 

Although many diode lasers work as multimode lasers, the distributed feedback (DFB) and distributed Bragg reflector (DBR) lasers show a mode selection because of their periodic structure. The mode selectivity is generated by the optical properties of the periodic stmctures because (Mily the modes that are associated with a standing wave/stop band are amplified. DFB structures are photonic structures, which are doped throughout the volume with chromophores (in an optimal case at the maxima of the standing waves), whereas DBR lasers have a miniature Fabry-Perot cavity in which the dye is localized, and the mirrors are replaced by periodic gratings [85]. 

In recent years, semiconductor fabrication techniques have progressed to an extent that permits the construction of highly complex integrated devices such as the distributed Bragg-reflector (DBR) laser diode shown in Figure 7-9. This device contains a gallium arsenide /in-junction diode that produces infrared radiation at about 975 nm. In addition, a stripe of material... 

Interference mirrors are dielectric thin film coatings where low- and high-refractive index layers alternate. The optical thickness of each of the layers is equal to quarter-wavelength QJAn). They are denoted as distributed Bragg mirrors or distributed Bragg reflectors (DBR), sometimes simply as Bragg mirrors. Other names include quarter-wave mirrors (QWM), quarterwave stacks (QWS) and highly reflective (HR) layers. 

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