Background:
In Code Division Multiple Access (CDMA)/Multi-Carrier CDMA (MCCDMA),
Walsh-Hadamard codes are widely used for its orthogonal characteristics, and hence, it leads
to good contextual connection property. These orthogonal codes are important because of their various
significant applications.
Objective:
To use the Mach–Zehnder Interferometer (MZI) for all-optical Walsh-Hadamard codes is
implemented in this present paper.
Method:
The Mach–Zehnder Interferometer (MZI) is considered for the Tree architecture of Semiconductor
Optical Amplifier (SOA). The second-ordered Hadamard and the inverse Hadamard matrix
are constructed using SOA-MZIs. Higher-order Hadamard matrix (H4) formed by the process of
Kronecker product with lower-order Hadamard matrix (H2) is also analyzed and constructed.
Results:
To experimentally get the result from these schemes, some design issues e,g Time delay, nonlinear
phase modulation, extinction ratio, and synchronization of signals are the important issues. Lasers
of wavelength 1552 nm and 1534 nm can be used as input and control signals, respectively. As
the whole system is digital, intensity losses due to couplers in the interconnecting stage may not create
many problems in producing the desired optical bits at the output. The simulation results were obtained
by Matlab-9. Here, Hadamard H2 (2×2) matrix output beam intensity (I ≈ 108 w.m-2) for different
values of inputs.
Conclusion:
Implementation of Walsh-Hadamard codes using MZI is explored in this paper, and experimental
results show the better performance of the proposed scheme compared to recently reported
methods using electronic circuits regarding the issues of versatility, reconfigurability, and compactness.
The design can be used and extended for diverse applications for which Walsh-Hadamard codes
are required.
Mach-Zehnder interferometer (MZI) with more than 20 dB extinction ratio on silicon-on-insulator