Coupling Loss

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). 

The ability to measure small index perturbations, (I/Ven. depends on the depth (i.e., the extinction ratio at resonance) and width of these resonances. The depth and width in turn depend on the relative values of the coupling coefficient t and the resonator loss a. Figure 9.16 shows typical ring resonator spectra calculated for two different loss values. The maximum extinction ratio is obtained at critical coupling when t = a, and the output intensity at resonance is exactly zero. The width of the resonances depends on the total round trip resonator loss, at, which is the product of waveguide losses within the ring (a) and coupling loss (t) at the coupler. 

The type of driver will be specified by the purchaser. The driver shall be sized to meet the maximum specified operating conditions, including bearing, mechanical seal, external gear, and coupling losses, as applicable, and shall be in accordance with the applicable specifications, as stated in the inquiry specification, data sheets, and order. The driver shall be suitable for satisfactory operation under the utility and site conditions specified. 

Propagation losses through active materials are a serious concern however, these typically contribute only a small fraction to the total insertion loss. The most serious problem relating to minimization of optical loss with use of electro-optic modulators is that of loss associated with mode mismatch between passive and active optical circuitry. When tapered transitions and other device structures discussed in this review are used to reduce optical loss associated with mode mismatch, total device insertion losses in the order of 4-6 dB are obtained. Without such adequate attention to coupling losses, insertion loss can be 10 dB or greater. 

Basic properties of radiating cables Measuring method of the coupling loss (2)... 

A given mesh reflectivity imposes a lower bound for the beam-waist radius, below which appreciable coupling losses can occur. The basic problem is that a Gaussian beam will continue to diverge upon repeated reflection within a planar interferometer as shown in Fig. 12b. If the spherical mirror of the cavity is designed to match the original (input) beam waist, beam divergence will cause a mismatch at the output, which... 

Arnaud et al. gave an expression that leads to the following criterion for restricting the coupling loss to 1 dB or less ... 

Treatment of an a-bromoketone with pentacarbonyliron results in coupling, loss of Br and formation of 1,4-diketones (eq (3)) [23]. 

A transformer model was devised for the coupling-loss mechanism associated with multifilament superconductors or cable conductors. The model is based on the fact that the loss is induced by an external magnetic field. A physical understanding of such induction phenomena can be obtained by analyzing an equivalent transformer circuit where the conductor is visualized as the secondary circuit with a time constant tq = L2/R2, and the exciting field is modeled as the primary circuit with a current, ii. For the filamentary superconductor, the time constant tq was chosen to be the same as that defined in field theory [% i.e.. 

Fig. 8. Normalized coupling loss per unit volume at B = 2T as a function of discharge time for three triplex conductors and the insulated single strand. The hysteretic loss at 2T is AO/V =...

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