Programmable fiber Bragg gratings for spectral CDMA

Summary form only given.The employment of optical code-division multiple-access (OCDMA) offers high advantages in allocating bandwidth for bursty access networks, where wide bandwidth services are required. Many different optical CDMA implementations have been proposed. Spectral slicing appears an attractive technique because spectral data encoding provides a large number of simultaneous users and transparency to data format and bit-rate. CDMA realized by using a cascade of fiber Bragg gratings (FBGs) allows to combine all the advantages of spectral encoding with the compactness and robustness of a totally guiding structure without free-space architectures losses. In this paper we experiment on FBG technology in order to realize spectral CDMA with programmable encoding. The cascade of 8 FBGs is used in encoding/decoding operation: each grating can be tuned independently by means of piezoelectric elements in order to program the desired user code.