CÁC THÔNG TIN ĐƯỢC PHÂN PHỐI pptx

... nhị phân, ta phải xét đến bằng cách các lỗi xuất hiện trong hệ thống lỗi trực giao. Số lượng tổng hợp của log 2 M C n là số khả năng nbit nhị phân ngoài log 2 M bit có thể bị lỗi. Đối với các ... độ rộng băng sử dụng. Như tên gọi, tin tức số được truyền đi một cách đơn giản bằng cách dịch tần số sóng mang một lượng nhất định tương ứng với mức nhị phân 1 và 0. Hình 3-1. vẽ q...

Ngày tải lên: 24/07/2014, 04:20

... P  Á E R z À  ÀÁ E S z À  ÀÁ "# ð10:42Þ where P  is the phase discontinuity matrix, which causes the complex electric field delay of  at z ¼ z  . By applying the phase discontinuity to eqn (10.26) and following the steps below ... equations are also discussed in detail. By converting the coupled wave equations into a matrix equation, these transfer matrices can represent the wave pr...

Ngày tải lên: 15/12/2013, 04:15

... alleviated by adopting dispersion-shifted or dispersion-flattened fibre [15,16]. Alternatively, semiconductor lasers oscillating in single longitudinal modes were developed [17,18]. By limiting the spread ... possible FP mode in these grating structures, it is quite usual to have anti-reflective coatings on the laser facets of DFB and DBR lasers. The working principle of a uniform-grating DFB la...

Ngày tải lên: 15/12/2013, 04:15

... second-order corrugation is used. However, the design of the second-order grating requires a precise control of the grating parameters. It is shown in the contour map that certain corrugation shapes ... The range of accuracy is extended by adopting a parabolic model [9] such that g peak ¼ aN 2 þ bN þ c ð2:52Þ where a, b and c are constants determined by fitting the available exact solutions us...

Ngày tải lên: 15/12/2013, 04:15

... equation within a reasonable range of error. Starting with different initial guesses of ð; Þ ini , other oscillating modes can be determined in a similar way. By collecting all ð 0 ; 0 Þ pairs that satisfy ... particular section. Since the discontinuity caused by the phase slip is assumed to be very small, the waves in the two sections can be considered to be continuous at z ¼ 0. In other...

Ngày tải lên: 15/12/2013, 04:15

... the –continuous change in laser cavity corrugation period Tapered corrugation large number –  varies along the –continuous change in laser cavity corrugation depth g N-layer surface emitting N ... matching approach, the TMM is more robust and flexible. By converting the coupled wave equations into a matrix equation, the wave propagating characteristics of the corrugated DFB section can be rep...

Ngày tải lên: 15/12/2013, 04:15

... the PSP shifts, there is a continuous change in the resonant cavity formed by the DFB laser such that the actual lasing mode may alter. At ¼ 0:77, it is interesting to see how all L values converge ... where the place of corrugation change coincides with the position of phase shift, it is interesting to show how ÁL drops to a local minimum. Figure 5.25 shows the dependence of the flatness up...

Ngày tải lên: 15/12/2013, 04:15

... coefficient ¼ 4  10 3 m À1 Cavity length L ¼ 500 mm Optical confinement factor À ¼ 0:35 Grating period à ¼ 227:039 nm Grating phase at the left facet  in rad Bragg wavelength ! B ¼ 2Ã=n 0 ¼ 1:55 mm Threshold ... refractive index at threshold can be found to be n th ¼ n ini þ À @n @N N th ð6:18Þ By substituting  ¼  th in eqn (6.5) at the threshold condition, the threshold wavelength ! th can...

Ngày tải lên: 15/12/2013, 04:15

... parameters used are listed in the inset. As with the QWS laser structure, distinct peaks which correspond to different oscillating modes are observed along the spectrum. When the biasing current increases, ... Á NN becomes influential. By adopting a longitudinally dependent coupling coefficient , the gain margin and the field uniformity of the DCC þ QWS DFB LD are improved. Continuous tuning a...

Ngày tải lên: 15/12/2013, 04:15

... element in the connecting matrix is unity only if a connection allows a pulse to travel from port i of node m to port j of node n. In the example given in Fig. 8.3, the connecting matrix C may be ... and terminal loads. The voltage pulses then enter the phase stubs to be delayed before they continue propagating along the main transmission line. The three-port circulator at the left facet (sec...

Ngày tải lên: 15/12/2013, 04:15