Intrinsic losses

The best fibers, installed in systems operating at 0.9 )J.m, had losses of 5 dB/km. The lower intrinsic losses in the 1.3 to 1.55-)J.m window were unattainable by this technique. Fundamental cation—oxygen vibrational modes as well as OH contamination were intrinsic to the compositions. 

The primary requirement for making any connection is to minimise the optical power that is lost in it. Intrinsic losses result from technological variations of the fibres to be connected i.e. core area mismatch, numerical aperture mismatch, and profile mismatch. These obvious errors can only be omitted by proper matching of connected fibres or additional optical elements should be used. Contrary to the intrinsic losses, extrinsic ones can be corrected by a mechanical alignment. Extrinsic losses are caused if ends of the fibres are in some distance and the light from the input fibre cannot be collected by the sink fibre. A similar situation with power losses occurs in lateral displacement and angular misalignment. 

In practice, very few applications of FEWS sensors can be found outside laboratory applications and demonstration systems. In the near-IR, suitable fibres are readily available but usually there is no real necessity to use them. Possible transmission pathlengths are sufficiently large to allow using standard transmission probes, while turbid samples can be measured using transflection or diffuse reflection probes. In the mid-IR, high intrinsic losses, difficulties in fibres handling and limited chemical and mechanical stability limit the applicability of optical fibres as sensor elements. 

If x = 1, critical coupling is obtained and the dip depth attains its maximum value of 100% the microresonator is said to be undercoupled if x < 1 and overcoupled for x > 1. While the coupling loss remains constant, the effective intrinsic loss can be changed by interaction of the evanescent fraction (/) of the WGM with the surrounding medium. The effective loss coefficient can then be written as a = a +/aa f /as, where the three terms denote true intrinsic loss, absorption (and perhaps also scattering) by the analyte, and absorption in the solvent (or ambient). 

Let the effective loss coefficient now include, in addition to intrinsic loss, a contribution due to absorption (and scattering) by the analyte contained in the evanescent fraction/of the WGM y = yx +/xa. The effect of the analyte on the resonant (single-frequency) drop signal D0a, when analyte absorption is a small fraction of the total loss, can be written in terms of an approximate effective absorption path length Leff as defined below ... 

In microwave dielectric ceramics, the extrinsic dielectric loss dominates. However, the intrinsic losses shonld be stndied to control and predict the dielectric properties at microwave freqnencies. 

Extrinsic dielectric loss in the microwave Ereqnency range is related to microstructure, secondary phases, and processing conditions. Intrinsic loss, however, represents the minimnm loss related to the lattice anharmonicity that can be expected for a particnlar material composition and crystal structure. It plays a... 

Far-IR reflectivity spectra of the (Pbo 5Cao 5)(Eeo 5Tao 5)03 specimens sintered at 1250°C for 30 min were taken to calculate the intrinsic dielectric loss at microwave frequencies. The spectra of the specimens were fitted by 10 resonant modes. The calculated reflectivity spectra are well fitted with the measured ones, as shown in Figure 22.4 and Table 22.2. The dispersion parameters of the specimens in Table 22.2 were determined by the Kramers-Kronig analysis and the classical oscillator model. The calculated values were higher than the measured ones by Hakki and Coleman s method, which is due to extrinsic effects such as grain size and porosity. Assuming the mixture of dielectrics and spherical pore with 3-0 connectivity, the measured loss quality also depends on the porosity as well as the intrinsic loss of materials, and Equation 22.24 may be modified for the loss quality, as in Equation 22.25 ... 

With the intrinsic loss obtained from far-lR reflectivity and porosity, the loss quality predicted by Equation 22.25 is shown in Figure 22.5, with the measured ones by Hakki and Coleman s method for comparison. The predicted loss qualities are consistent with the measured ones. In general, Qf values do not follow the... 

The general expression for attenuation or the intrinsic loss of light intensity in a glass is given by,... 

Intrinsic losses are related to the molecular-level interaction of ultrasound with the material of the homogeneous phases making up the disperse system. Ultrasonic waves undergo partial attenuation when they propagate through any homogeneous system. For example, in water this attenuation is very low, 20 dB/cm at 100 MHz [33], In disperse... 

A comparison of dG with (dG B — dGg) provides a lower limit to the intrinsic loss of entropy upon binding A (Eqn. 73). 

In general, intrinsic loss of strength in shale solely due to temperature changes is not important, as these changes are rarely more than 30°C, and they can be neglected as compared to the effects that temperature has on stresses and diffusive processes. 

Scattering. Fluctuations in composition and density of the glass occur as it cools down below Tg, the resulting scattering is a form of Rayleigh scattering. We can describe the intrinsic loss, L, mathematically by... 

Figure 6 Extrinsic and intrinsic loss features in XPS. (A) CuO Cu 2p shake-up sateiiites, (B) C Is and n->n shake-up satellite, (C) NiO Ni 2p shake-up and multiplet splitting, and (D) Al plasmon loss feature from pure aluminum.

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