Analysis of the spectral efficiency of frequency-encoded OCDMA systems with incoherent sources

Rochette, Martin; Ayotte, S.; Rusch, Leslie A.

doi:10.1109/jlt.2005.844201

Cited by 41 publications

(31 citation statements)

References 10 publications

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“…These overlapped bins can be represented mathematically by AND operation between the active user and interferers [8]. This technique can be performed using the inexpensive fiber Bragg-gratings (FBGs) to decode the received signal because of their low insertion losses, good spectral resolution, small size, and light weight [10]. The photo detector is composed of two photodiodes (PD and s-PD) which are connected electrically in opposition.…”

Section: Detection Techniques 21 Modified-and Subtraction Detectionmentioning

confidence: 99%

“…for active user or  P.U. for interferers, where the weight w represents the number of occupied frequency bins in the user's encoder, and the in-phase cross-correlation  is the maximum number of common frequency bins occupied by any two codes of the family [10]. The remainder of the signal from the decoder is then transmitted to the subtractive decoder (s-Decoder) to cancel out signals with mismatched signatures, i.e., interferers.…”

Section: Single Photodiode Detectionmentioning

confidence: 99%

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SAC- OCDMA System Using Different Detection Techniques

Somaya¹,

Mottaleb²,

Fayed³

et al. 2014

IOSRJECE

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:In this paper, we investigate the optimum received power for spectral amplitude coding optical code division multiple access (SAC-OCDMA) INTRODUCTIONRecently, optical code division multiple access (OCDMA) technique is getting more attractive due to its several features as its ability to support asynchronous access, bursty traffic, secure transmission and effective cost [1,2]. The main drawback of OCDMA is that its performance and capacity are limited by multiple access interference (MAI) [3,4]. Researchers proposed spectral amplitude coding (SAC) from all types of OCDMA due to its ability in restrain MAI when using a suitable detection technique at the receiver with fixed in-phase cross correlation codes [5]. Low cost broadband sources such as light emitting diodes (LEDs) can be used for SAC-OCDMA system. However, the performance of SAC-OCDMA is still limited by phase induced intensity noise (PIIN) that results from using broadband light sources [6]. Modified-AND subtraction detection technique and SPD detection technique are used for reducing PIIN and MAI [7].In this work, enhanced double weight codes (EDW) are used as the signature codes for SAC-OCDMA systems with modified-AND subtraction detection and SPD detection techniques when APDs are used.The remainder of this paper is organized as follows. In Sec 2, we give a detailed explanation about the detection techniques, followed by the network simulation setup in Sec.3. Section 4 is devoted for the results and discussion. Finally, the conclusion of the paper is provided in Sec.5. II. DETECTION TECHNIQUES 2.1 MODIFIED-AND SUBTRACTION DETECTIONThe SAC-OCDMA receiver diagram of this technique is shown in Fig. 1 [7]. The received optical signal is split by splitter 1 into two parts, one to the upper decoding branches and the other to the AND decoder through an attenuator. The attenuator ensures that, the interference signal has an equivalent power incident on each photo detector in the case of an inactive user. The decoder filters are placed in a parallel configuration. This structure divides the spectrum of the decoded signals. It is worth to note that, both splitters (1 and 2) and the attenuator could be replaced by a single coupler with an appropriate coupling ratio in order to get a more cost-effective receiver. The decoder has a spectral response matched to the active user, whereas the AND decoder has overlapped bins from different interferers. These overlapped bins can be represented mathematically by AND operation between the active user and interferers [8]. This technique can be performed using the inexpensive fiber Bragg-gratings (FBGs) to decode the received signal because of their low insertion losses, good spectral resolution, small size, and light weight [10]. The photo detector is composed of two photodiodes (PD and s-PD) which are connected electrically in opposition. The output signal is proportional to the power difference of the two optical inputs. In the presence of an interferer, the difference between the two signals is cancelled o...

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Section: Detection Techniques 21 Modified-and Subtraction Detectionmentioning

confidence: 99%

Section: Single Photodiode Detectionmentioning

confidence: 99%

SAC- OCDMA System Using Different Detection Techniques

Somaya¹,

Mottaleb²,

Fayed³

et al. 2014

IOSRJECE

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“…They are made of bins of a given spectral width that are fully transmissive or fully opaque, and c E (i) and c D (i) denote the ith element of the encoder and decoder code words, respectively. The PIIN expression for unpolarized thermal light source can be evaluated as [5]:…”

Section: Single Photodiode Detection (Spd) Schemementioning

confidence: 99%

Improving spectral efficiency of SAC-OCDMA systems by SPD scheme

Al-Khafaji

Aljunid

Amphawan

et al. 2012

IEICE Electron. Express

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This letter presents a single photodiode detection (SPD) as an effective technique for eradicating both multiple-access interference (MAI) and phase-induced intensity noise (PIIN) in spectralamplitude coding optical code-division multiple-access (SAC-OCDMA) systems. Mathematical analysis and simulation experiments are used to investigate the spectral efficiency (SE) of SAC-OCDMA systems utilizing different detection techniques. Results show that the SPD technique significantly enhances the SE compared to AND as well as modified-AND subtraction detections. Keywords: SAC-OCDMA, single photodiode detection (SPD), spectral efficiency (SE), MAI, PIIN Classification: Fiber optics, Microwave photonics, Optical interconnection, Photonic signal processing, Photonic integration and systems References[1] S. B. Ahmad-Anas, M. K. Abdullah, M. Mokhtar, and S. D. Walker, "Multiple access interference elimination with enhanced chromatic dispersion tolerance in SAC OCDMA," IEICE Electron. Express, vol. 5, no. 16, pp. 617-623, Aug. 2008. [2] H. M. R. Al-Khafaji, S. A. Aljunid, and H. A. Fadhil, "Improved BER based on intensity noise alleviation using developed detection technique for incoherent SAC-OCDMA systems,"

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“…Beat-noise reduction in SAC OCDMA systems has been investigated by a number of groups [9]- [11] who have focused on developing code families with minimal in-phase cross correlation between channels in order to reduce the total amount of interchannel beating at each detector. This is achieved by generating codes with reduced weight (the number of "ones" in each code sequence) relative to code length.…”

Section: Introductionmentioning

confidence: 99%

Feasibility Study of SOA-Based Noise Suppression for Spectral Amplitude Coded OCDMA

McCoy

Ibsen

Horák

et al. 2007

J. Lightwave Technol.

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Abstract-We investigate the benefits of employing a saturated semiconductor optical amplifier (SOA) to reduce the optical noise in an incoherent light optical code division multiple access (OCDMA) system. In the context of spectrum slicing, SOA-based noise suppression has shown significant potential in enhancing the signal quality of noisy light. In this paper, we evaluate the viability of the technique for spectral amplitude coded OCDMA and show that the benefits of SOA-based noise suppression do not extend readily to this application due to post-SOA opticalfiltering effects at the receiver. However, appreciable performance improvements can in principle be realized through optimized system and decoder design.Index Terms-Optical code division multiple access (OCDMA), optical noise, semiconductor optical amplifier (SOA).

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Analysis of the spectral efficiency of frequency-encoded OCDMA systems with incoherent sources

Cited by 41 publications

References 10 publications

SAC- OCDMA System Using Different Detection Techniques

SAC- OCDMA System Using Different Detection Techniques

Improving spectral efficiency of SAC-OCDMA systems by SPD scheme

Feasibility Study of SOA-Based Noise Suppression for Spectral Amplitude Coded OCDMA

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