TOAD-Based Frequency-Encoded All Optical …
179
G(t) = exp[h(t)]
(3)
where h(t) is [11]
h(t) = − ln
1 −
1 −
1
G 0
exp
−
E c (t)
E s
(4)
E s being saturation energy and E c (t), control pulse energy of the SOA.
We have used the Soliton pulses as control inputs [10, 11]
P i (t) =
n=N
n=1
a n A,B P soli sec h
2
1.763
(t − nχ)
τ fwhm
(5)
where P soli =
1.763
2π
2 A eff λ
3 D m
n 2 cτ
2
fwhm
gives the Soliton peak power, D m , the dispersion constant, n 2 is the nonlinear refractive index coefficient, λ and c denote
the wavelength and velocity of light, respectively, A eff is the effective area of
the fiber,τ fwhm gives the full width half maximum, χ gives the bit period. E cp
(t → ∞) = P soli × τ fwhm = E c , total control pulse energy. The control signal and
data signal have different frequencies υ 1 or υ 2 for proper operation in co propagation
scheme.
3 Frequency-Encoded XOR Gate for SUM Generation
Frequencies υ 1 and υ 2 with corresponding wavelengths are 1550 nm and 1560 nm,
respectively, denotes the states ‘0’ and ‘1’. Design of frequency-encoded XOR gate
using TOAD as shown in Fig. 2. It has two inputs A, B and one output. It is consist
of 7 TOADs, T 1 , T 2 , T 3 , T 4 , T 5 , T 6 , T 7 . The following is the operation of the XOR
gate:
Case (1): When input A is a signal of frequency υ 1 , the small portion of signals
through the υ 1 pass filter makes the control input of the TOAD T 1 is υ 1 and rest of the
signal passes through the υ 1 pass filter to make output of the TOAD T 5 to be υ 1 . In
this condition, the control signal of the TOAD T 1 forces the data signal of frequency
υ 2 transmitted through the port 1 of the TOAD T 1 and output of the TOAD T 1 is
υ 2 . Similarly, when input B is a signal at υ 1 , the small portion of signals through the
υ 1 pass filter makes the control input of the TOAD T 3 is υ 1 and remaining portion
of the signal, through the υ 1 pass filter makes the output of the TOAD T 6 at υ 1 . In
this condition, the control signal of the TOAD T 3 forces the data signal of frequency
υ 2 transmitted through the port 1 of the TOAD T 3 and output of the TOAD T 3 is
υ 2 . So both the outputs of TOAD T 5 and T 6 are signal frequency υ 1 , i.e., there is
no control signal receives of TOAD T 7 . During the absence of control, the SOAs
remains unsaturated, hence, the data signal of frequency υ 1 comes out at the port 2
of the TOAD T 7 thus the final output of the gate will be at frequency υ 1 , i.e., ‘LOW’.
179
G(t) = exp[h(t)]
(3)
where h(t) is [11]
h(t) = − ln
1 −
1 −
1
G 0
exp
−
E c (t)
E s
(4)
E s being saturation energy and E c (t), control pulse energy of the SOA.
We have used the Soliton pulses as control inputs [10, 11]
P i (t) =
n=N
n=1
a n A,B P soli sec h
2
1.763
(t − nχ)
τ fwhm
(5)
where P soli =
1.763
2π
2 A eff λ
3 D m
n 2 cτ
2
fwhm
gives the Soliton peak power, D m , the dispersion constant, n 2 is the nonlinear refractive index coefficient, λ and c denote
the wavelength and velocity of light, respectively, A eff is the effective area of
the fiber,τ fwhm gives the full width half maximum, χ gives the bit period. E cp
(t → ∞) = P soli × τ fwhm = E c , total control pulse energy. The control signal and
data signal have different frequencies υ 1 or υ 2 for proper operation in co propagation
scheme.
3 Frequency-Encoded XOR Gate for SUM Generation
Frequencies υ 1 and υ 2 with corresponding wavelengths are 1550 nm and 1560 nm,
respectively, denotes the states ‘0’ and ‘1’. Design of frequency-encoded XOR gate
using TOAD as shown in Fig. 2. It has two inputs A, B and one output. It is consist
of 7 TOADs, T 1 , T 2 , T 3 , T 4 , T 5 , T 6 , T 7 . The following is the operation of the XOR
gate:
Case (1): When input A is a signal of frequency υ 1 , the small portion of signals
through the υ 1 pass filter makes the control input of the TOAD T 1 is υ 1 and rest of the
signal passes through the υ 1 pass filter to make output of the TOAD T 5 to be υ 1 . In
this condition, the control signal of the TOAD T 1 forces the data signal of frequency
υ 2 transmitted through the port 1 of the TOAD T 1 and output of the TOAD T 1 is
υ 2 . Similarly, when input B is a signal at υ 1 , the small portion of signals through the
υ 1 pass filter makes the control input of the TOAD T 3 is υ 1 and remaining portion
of the signal, through the υ 1 pass filter makes the output of the TOAD T 6 at υ 1 . In
this condition, the control signal of the TOAD T 3 forces the data signal of frequency
υ 2 transmitted through the port 1 of the TOAD T 3 and output of the TOAD T 3 is
υ 2 . So both the outputs of TOAD T 5 and T 6 are signal frequency υ 1 , i.e., there is
no control signal receives of TOAD T 7 . During the absence of control, the SOAs
remains unsaturated, hence, the data signal of frequency υ 1 comes out at the port 2
of the TOAD T 7 thus the final output of the gate will be at frequency υ 1 , i.e., ‘LOW’.