恶成语顾婉怡光纤通信答案
Fiber optic communication, people's post office answer fiber communication after class
Chapter one basic theory
谷氨酰胺转氨酶1, what is the principle of single mode transfer of the first step refractive index fiber?
傲慢的英语A: angelica sinensis, a frequency V is smaller than that of the cond order mode LP11 normalized cut-off frequency, 0 < V < 2.40483, namely There is only one transfer mode in the pipeline, that is single mode transmission.
How does the loss of the pipeline and dispersion affect the optical fiber communication system?
A: in optical fiber communication systems, optical fiber loss is one of the important factors that restrict WuZhongJi communication distance, to a large extent determines the transmission system of relay distance; The dispersion of the optical fiber caus the distortion of the transmission signal, reducing the communication quality, thereby limiting the communication capacity and the communication distance.
What kind of dispersion is in the fiber optic? Explain what it means.
Answer: (1) the mode dispersion: there are many in the multimode fiber transmission mode, different mode along the fiber axial transmission speed is different, the time arrived at the
receiving end, and the mode dispersion.
(2) the material dispersion: due to the refractive index of optical materials is the nonlinear function of wavelength, so that the transmission speed changes over the wavelength of light, the resulting dispersion is called the material dispersion.
女人如何撒娇(3) the waveguide dispersion: the pha constant of the uniform mode is changed with the wavelength, the group velocity varies with the wavelength, and the resulting dispersion is called the waveguide dispersion.
How does the fiber optic nonlinear effect affect the optical fiber communication system?
Answer: the nonlinear effect of optical fiber in optical fiber communication system has both positive and negative influence, on the one hand, can cau additional loss of transmission signal of the crosstalk between channels in WDM system and mobile signal carrier and so on, on the other hand, can be ud to develop new devices such as amplifier, modulator.
What kinds of single mode fiber?
Answer: the single mode fiber can be divided into four categories: the dispersion-shifted single-mode fiber, dispersion-shifted single-mode optical fiber, cutoff wavelength displacement single-mode optical fiber, nonzero dispersion displacement single-mode fiber.
What are the parts of the cable?
Answer: strengthen piece, cable core, exterior guard layer.
*, the advantages of fiber optics: great bandwidth (200THz), small loss of transmission, light weight, electromagnetic interference, and metal saving.
*, optical fiber loss: the attenuation of optical fiber by optical fiber. Caus of fiber loss: the loss, manufacturing loss, and the added loss. *, optical fiber dispersion: due to the optical fiber transmission signal is carried by the different frequency components and different model components, different frequency components and different model components of transmission speed is different, lead to signal distortion. The cau of optical fiber dispersion: the light signal is not a single color, the optical fiber is the dispersion effect of the light signal. Dispersion type: pattern disper
sion (different modes of wavelength), material dispersion (refractive index), waveguide dispersion (same pattern, pha constant).
Single mode fiber: the optical fiber that transmits a single ba mode at a given working wavelength.
Chapter ii light source and light transmitter
What are the three basic process of light and matter? What are their respective characteristics?
Answer: (1) spontaneous radiation: the spontaneous behavior of
芙蓉嶂水库high level electrons has nothing to do with whether there are external incentives; Spontaneous radiation can occur in a range of levels, and the spectrum of emission from this material is wide; Even if the transition process to meet the same energy level difference, and they are independent, the random radiation, the photon energy is the same and have nothing to do with each other, each column of light waves can have different pha and polarization direction, and spread to all aspects of space, is a kind of incoherent light.
(2) stimulated radiation: the energy of the induced photon is the difference between the energy levels of the downward transition; The photons that are generated by the stimulated radiation are all
the same photons, and they are coherent; The stimulated radiation process is esntially a magnifying process of external incident light.
(3) stimulated absorption: external light energy needs to be consumed when stimulated absorption; The stimulated absorption process corresponds to the absorption of the photon, which generates the photoelectric conversion process of the electron.
What is a population inversion?
A: the number of particles in a high energy state is greater than the number of particles in the lower energy state.
How to achieve light amplification?
洗衣店投资
Answer: make the electron density on the medium and high energy
level is greater than the low level of electron density, the stimulated radiation dominate, light pass through a medium strength according to the index law growth, waves are amplified, then realize the optical amplification.
What are the functional components that constitute a lar?
绿茸茸Answer: the source area, the light feedback device, the frequency lection element, the direction of the beam, the light waveguide.
插翅难飞的意思What are the methods for optical cavity? What are the corresponding lar types?
Answer: (1) the crystal natural cleavage plane form method in - perot cavity (F - P cavity), when the light in the cavity to satisfy a certain pha and resonance conditions, to establish a stable light oscillation;
(2) using periodic corrugated structures on one side of the source region to provide optical coupling to form optical oscillations.
*, the general conditions of ejection: (1) there are sufficient number of population inversion distributions in active regions;
(2) there is an optical resonance mechanism, and a stable lar oscillation is established in the active area
Chapter iii optical receiver
