Distributed Bragg Reflector Laser

picture info	Distributed Bragg Reflector Laser A distributed Bragg reflector laser (DBR) is a type of single frequency laser diode. Other practical types of single frequency laser diodes include DFB DFB may refer to: * Deerfield Beach, Florida, a city * Decafluorobutane, a fluorocarbon gas * Dem Franchize Boyz, former hip hop group, Atlanta, Georgia * Dfb, Köppen climate classification for Humid continental climate * Distributed-feedback ... lasers and external cavity diode lasers. A fourth type, the cleaved-coupled-cavity laser has not proven to be commercially viable. VCSELs are also single frequency devices. The DBR laser structure is fabricated with surface features that define a monolithic, single mode ridge waveguide that runs the entire length of the device. A resonant cavity is defined by a highly reflective DBR mirror on one end, and a low reflectivity cleaved exit facet on the other end. Within the cavity is a gain ridge portion, where current is injected to produce a single spatial lasing mode. The DBR mir ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	DBR Laser Schematic DBR may refer to: * Daniel Bernard Roumain, composer and violinist * DBR Class of diesel locomotive, New Zealand * ''De Bellis Renationis'', renaissance wargaming rules * Design-based research in the learning sciences * Deuterium bromide, chemical formula DBr * Distributed Bragg reflector, used in waveguides * Dowel bar retrofit, highway crack treatment * Drum-Buffer-Rope, in the theory of constraints * ДБР, State Bureau of Investigation (Ukraine) Codes * Bad Doberan, Germany, vehicle license plate * Derby Road (Ipswich) railway station, National Rail code DBR * DutchBird, airline ICAO code DBR * Dobrolet (low-cost airline) Dobrolet LLC (russian: ООО «Добролёт» , translit = OOO Dobrolyot) was a Russian low-cost airline - a subsidiary of Aeroflot - based at Sheremetyevo International Airport. It operated scheduled flights to domestic destinations. Hi ... , airline ICAO code DBR {{disambig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
picture info	Distributed Bragg Reflector A distributed Bragg reflector (DBR) is a reflector used in waveguides, such as optical fibers. It is a structure formed from multiple layers of alternating materials with varying refractive index, or by periodic variation of some characteristic (such as height) of a dielectric waveguide, resulting in periodic variation in the effective refractive index in the guide. Each layer boundary causes a partial reflection of an optical wave. For waves whose vacuum wavelength is close to four times the optical thickness of the layers, the many reflections combine with constructive interference, and the layers act as a high-quality reflector. The range of wavelengths that are reflected is called the photonic stopband. Within this range of wavelengths, light is "forbidden" to propagate in the structure. Reflectivity The DBR's reflectivity, R, for intensity is approximately given by :R = \left frac\right2, where n_o,\ n_1,\ n_2 and n_s\, are the respective refractive indices of the or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
picture info	Laser Diode file:Laser diode chip.jpg, The laser diode chip removed and placed on the eye of a needle for scale A laser diode (LD, also injection laser diode or ILD, or diode laser) is a semiconductor device similar to a light-emitting diode in which a diode pumped directly with electrical current can create active laser medium, lasing conditions at the diode's p–n junction, junction. Driven by voltage, the doped p–n-transition allows for Carrier generation and recombination, recombination of an electron with a Electron hole, hole. Due to the drop of the electron from a higher energy level to a lower one, radiation, in the form of an emitted photon is generated. This is spontaneous emission. Stimulated emission can be produced when the process is continued and further generates light with the same phase, coherence and wavelength. The choice of the semiconductor material determines the wavelength of the emitted beam, which in today's laser diodes range from infra-red to the UV spectrum ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Distributed Feedback Laser A distributed-feedback laser (DFB) is a type of laser diode, quantum-cascade laser or optical-fiber laser where the active region of the device contains a periodically structured element or diffraction grating. The structure builds a one-dimensional interference grating (Bragg scattering), and the grating provides optical feedback for the laser. This longitudinal diffraction grating has periodic changes in refractive index that cause reflection back into the cavity. The periodic change can be either in the real part of the refractive index or in the imaginary part (gain or absorption). The strongest grating operates in the first order, where the periodicity is one-half wave, and the light is reflected backwards. DFB lasers tend to be much more stable than Fabry–Perot or DBR lasers and are used frequently when clean single-mode operation is needed, especially in high-speed fiber-optic telecommunications. Semiconductor DFB lasers in the lowest loss window of optical fibers at abo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Vertical-cavity Surface-emitting Laser The vertical-cavity surface-emitting laser, or VCSEL , is a type of semiconductor laser diode with laser beam emission perpendicular from the top surface, contrary to conventional edge-emitting semiconductor lasers (also ''in-plane'' lasers) which emit from surfaces formed by cleaving the individual chip out of a wafer. VCSELs are used in various laser products, including computer mice, fiber optic communications, laser printers, Face ID, and smartglasses. Production advantages There are several advantages to producing VCSELs, in contrast to the production process of edge-emitting lasers. Edge-emitters cannot be tested until the end of the production process. If the edge-emitter does not function properly, whether due to bad contacts or poor material growth quality, the production time and the processing materials have been wasted. VCSELs however, can be tested at several stages throughout the process to check for material quality and processing issues. For instance, if the v ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Distributed Bragg Reflector A distributed Bragg reflector (DBR) is a reflector used in waveguides, such as optical fibers. It is a structure formed from multiple layers of alternating materials with varying refractive index, or by periodic variation of some characteristic (such as height) of a dielectric waveguide, resulting in periodic variation in the effective refractive index in the guide. Each layer boundary causes a partial reflection of an optical wave. For waves whose vacuum wavelength is close to four times the optical thickness of the layers, the many reflections combine with constructive interference, and the layers act as a high-quality reflector. The range of wavelengths that are reflected is called the photonic stopband. Within this range of wavelengths, light is "forbidden" to propagate in the structure. Reflectivity The DBR's reflectivity, R, for intensity is approximately given by :R = \left frac\right2, where n_o,\ n_1,\ n_2 and n_s\, are the respective refractive indices of the or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]