14-04-2013, 06:26 PM
Kindlt tell me the solution of this question:
3.26 Consider an EDFA that is required to amplify wavelengths between 1532 nm and
1550 nm within the C-band (separated by 100 GHz).
(a) Draw a schematic of this basic EDFA, and assume the pump laser is selected
to minimize ASE. Also, be sure to prevent backward reflections at the EDFA
input/output.
(b) Draw the relevant energy bands and associated energy transitions between
these bands.
© How many wavelengths could be amplified within this range (and spacing)?
(d) Compute the required range in energy transitions to support the entire range
of wavelengths.
(e) Suppose we wanted to (1) add and drop a subset of these wavelengths at the
EDFA and (2) add a second stage that would be best suited for maximum
output powers. Please draw this new two-stage EDFA, with the add/drop
multiplexing function drawn as a “black box” labeled “ADM.”
(f) Now focusing on the “ADM,” assume that two fiber Bragg gratings (along
with associated circulator, splitters, and filters) are used to provide static drop
capability of the lowest two contiguous wavelengths in the spectral range. In
addition, a combiner is used to subsequently add these same wavelengths (of
course, carrying different embedded signals). Sketch the architecture for this
ADM (that is, the inside of the black box).
(g) If the effective refractive index of the ADM fiber segment is 1.5, calculate the
associated fiber Bragg grating periods.
