A new code structure for spectral-amplitude-coding optical code-division multiple-access system based on double-weight (DW) code families is proposed. The DW code has a fixed weight of two. By using a mapping technique, codes that have a larger number of weights can be developed. Modified double-weight (MDW) code is a DW code family variation that has variable weights of greater than two. The newly proposed code possesses ideal crosscorrelation properties and exists for every natural number n. Based on theoretical analysis and simulation, MDW code is shown here to provide a much better performance compared to Hadamard and modified frequency-hopping codes.

Abstract:In this paper, a multiwavelength linear-cavity Brillouin-Erbium fiber laser pumped by a 1480 nm pump laser is demonstrated to operate in the L-band region. The issue of low gain efficiency of L-band in Erbium-doped fiber pumped with 980 nm pump lasers is resolved with this pumping scheme. The amount of 1480 nm pump power to produce the first Brillouin Stokes line oscillating in the cavity is 23.4 mW only. The proposed laser configuration has a wide tuning range of 16 nm from 1591 to 1607 nm with six Brillouin Stokes lines within this tuning range. The maximum number of 23 Brillouin Stokes lines with a spacing of 0.089 nm is achieved by setting the Brillouin pump wavelength at 1595.5 nm and its power is set at 3.2 mW. Wavelength, nmOutput spectrum of L-band linear cavity BEFL at BP power of 3.2 mW, BP wavelength of 1595.5 nm and 1480 nm pump power is set to 100 mW

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An optical decoding technique is proposed for a spectral-amplitude-coding-optical code division multiple access, namely, the AND subtraction technique. The theory is being elaborated and experimental results have been done by comparing a double-weight code against the existing code, Hadamard. We have proved that the and subtraction technique gives better bit error rate performance than the conventional complementary subtraction technique against the received power level.

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This letter presents the effect of intracavity loss control on the tuning range of erbium-doped fiber laser (EDFL). The intracavity loss is controlled using a variable attenuator fitted inside the laser's cavity. The tuning range of uncontrolled cavity loss is around 3 nm, while the controlled cavity loss tuning range is 30 nm.