Full-Optical TOAD based Walsh-Hadamard code generation

摘要

Transmission of information takes place simultaneously over the same available channel bandwidth in Code Division Multiple Access (CDMA) technique. The spread spectrum (SS) technique is used in CDMA systems for transmission of information by employing spreading codes. A unique spreading code, acts as a signature code, is assigned for each individual user. The signal occupies a bandwidth much larger than the minimum necessary to send the information in SS modulation technique. A synchronized reception with the code at the receiver is applied for dispreading the information before the data recovery. From a long-term, Walsh-Hadamard codes have been employed as spread spectrum codes in CDMA communications due to their ease of generation. Walsh-Hadamard codes are absolutely orthogonal binary user codes which have so many favourite applications in synchronous multicarrier communications. However, the optical application of Walsh-Hadamard codes turns important for optical CDMA to solve the above problem. For this, the designs need the use of nonlinear optics capable of controlling multi-valued signals. To achieve this goal all-optical terahertz optical asymmetric Demultiplexer based design of Walsh-Hadamard codes is explored in this paper.