Mohamad Sayid Abdullah - Academia.edu (original) (raw)

Papers by Mohamad Sayid Abdullah

International journal of ophthalmology, 2016

The effect of self-phase modulation (SPM) on 40 Gb/s absolute polar duty cycle division multiplex... more The effect of self-phase modulation (SPM) on 40 Gb/s absolute polar duty cycle division multiplexing (AP-DCDM) is investigated and reported. The study includes the influence of launched power, number of channels and dispersion compensation method. Dispersion post-compensation and combination of dispersion pre- and post-compensation are used to manage the transmission links. At high powers, SPM degrades the pulse recompression process and provides an upper bound on the AP-DCDM transmitted pulse energy. It is demonstrated that the 40 Gb/s AP-DCDM system shows a 4.1 dB improvement and less than 1 dB penalty in terms of SPM tolerance in comparison to 40 Gb/s 4-ary and on – off-keying (OOK) systems, respectively. The SPM effect is stronger in the 100% post-compensated link than that in the combination of pre- and post-compensated links. Dispersion pre-compensation of 18–22% is found as the optimum range of pre-compensation ratio for AP-DCDM system, which makes optimisation of the launche...

2005 13th IEEE International Conference on Networks Jointly held with the 2005 IEEE 7th Malaysia International Conf on Communic

... Monir Abdullah, Mohamed Othman and Rozita Johari Department of Communication Technology and N... more ... Monir Abdullah, Mohamed Othman and Rozita Johari Department of Communication Technology and Network Faculty of Computer Science and Information Technology Universiti Putra Malaysia,Serdang, Selangor, Malaysia monabdullah ... [6] C. Qiao, R. Melhem, D. Chiarulli ...

2008 6th National Conference on Telecommunication Technologies and 2008 2nd Malaysia Conference on Photonics, 2008

A new multiplexing technique based on duty cycle division is proposed, thus the name duty cycle d... more A new multiplexing technique based on duty cycle division is proposed, thus the name duty cycle division multiplexing (DCDM). DCDM can be applied in both electrical and optical domains, for wired and wireless systems. The new technique allows for more efficient use of time slots as well as the spectrum, taking advantage of both the conventional TDM and FDM. In this paper, three channels operating at the same speed of 10 Gbps per channel are multiplexed in the electrical domain. The performance comparison is made against 3times10 Gbps TDM, and the experimental simulation results show that the DCDM system can support higher bit rate than TDM and also, it is less sensitive to the chromatic dispersion effect.

9th Asia-Pacific Conference on Communications (IEEE Cat. No.03EX732)

Increasing the bandwidth until the physical limit of the optical medium itself (fiber optics) has... more Increasing the bandwidth until the physical limit of the optical medium itself (fiber optics) has always been the striving goal in designing an optical fiber communication system. Wavelength division multiplexing (WDM) and its dense version (DWDM) are widely accepted as the best approaches thus far. In this paper, a study on the sub-carrier multiplexing at radio frequency (RF) bands is proposed as a complementary technique to increase the transmission bandwidth. Two channels (each at 155 Mbps rate) and eight channels (each at 622 Mbps rate) of pseudo-random bit sequence of the NRZ-encoded data were tested. The channels were sub-carried by two RF signals at 500 MHz and 1 GHz respectively, while the eight channels system were sub-carried by 1 GHz, 2 GHz, 3 GHz and 4 GHz over each of the two wavelengths. The simulations were carried out over a fiber distance of 70 km. The effect of transmission native rate on the selection of the sub-carrier frequency is also presented.

2008 6th National Conference on Telecommunication Technologies and 2008 2nd Malaysia Conference on Photonics, 2008

In this study the author has modeled and characterizes the performance of 3times10 Gbp/s absolute... more In this study the author has modeled and characterizes the performance of 3times10 Gbp/s absolute polar duty cycle division (APDCDM) multiplexing in dispersive environments at 1550 nm. APDCDM technique is examined, with comparison to non-return-to-zero (NRZ) and return-to-zero (RZ) time division multiplexing. In this paper three channel operating at the same speed of 10 Gbps are multiplexed in electrical domain. The experimental simulation results show that the receiver sensitivity of all users in APDCDM system is similar to that of RZ-TDM and 3 dB better than NRZ-TDM. The proposed system offer reduced dispersion sensitivity; this suggests advantages for APDCDM in optical multiplexing systems. It was also showed that APDCDM can support higher bit rate than TDM and also, it is less sensitive to the chromatic dispersion effect.

2008 6th National Conference on Telecommunication Technologies and 2008 2nd Malaysia Conference on Photonics, 2008

The authors propose a new multiplexing and demultiplexing technique based on return-tozero (RZ) d... more The authors propose a new multiplexing and demultiplexing technique based on return-tozero (RZ) duty cycle division, which is called absolute polar duty cycle division multiplexing (APDCDM). The new technique allows for more efficient use of time slots as well as spectrum. In this paper three users operating at the same speed of 2.5 Gb/s are multiplexed in electrical domain. The performance comparison is made against 7.5 Gb/s return-to-zero time division multiplexing (TDM) system. The experimental simulation results show that although APDCDM has the same receiver sensitivity as TDM but it is able to support higher distance and higher bit rate than TDM.

2008 6th National Conference on Telecommunication Technologies and 2008 2nd Malaysia Conference on Photonics, 2008

In is paper, the maximum power per chip to keep the Stimulated Raman Scattering (SRS)induced tilt... more In is paper, the maximum power per chip to keep the Stimulated Raman Scattering (SRS)induced tilt below a specific level in Spectral-Amplitude-Coding Optical Code-Division Multiple-Access (SAC-OCDMA) is evaluated for different number of users. A number of computer simulations have been conducted for this purpose. It is shown that as number of users grows, the power per chip must be decreased to control the SRS-induced tilt and to keep it below acceptable levels. It is also shown that SRS-induced tilt can significantly limit the power per chip levels when the number of users is large. This is the first time such a study is reported for OCDMA systems.

TENCON 2005 - 2005 IEEE Region 10 Conference, 2005

Abstract-Investigation of L-band linear cavity multiwavelength Brillouin-Erbium fiber laser sourc... more Abstract-Investigation of L-band linear cavity multiwavelength Brillouin-Erbium fiber laser source has been experimentally studied. The effects of Brillouin pump power and wavelength on the threshold pump power are discussed in the paper. We found that there is a limited range ...

ICSE'98. 1998 IEEE International Conference on Semiconductor Electronics. Proceedings (Cat. No.98EX187)

Page 1. ICSE'98 Proc., Nov. 1998, Bangi, Malaysia 105 TAPPER RATIO DEPEN... more Page 1. ICSE'98 Proc., Nov. 1998, Bangi, Malaysia 105 TAPPER RATIO DEPENDENCY OF A LOW-COST PASSIVE OADM SYSTEM Ruzita Abu Bakar*, Mohamad Khazani Abdullah, Fazlee Isnin, Harith Ahmad, and Burhanuddin ...

2006 2nd International Conference on Information & Communication Technologies

Abstract Cognitive radio (CR) is an emerging approach for a more efficient usage of the precious ... more Abstract Cognitive radio (CR) is an emerging approach for a more efficient usage of the precious radio spectrum resources, which it considers an expanded view of the wireless channel by managing and adapting various dimensions of time, frequency, space, power, ...

2007 IEEE International Conference on Telecommunications and Malaysia International Conference on Communications, 2007

Page 1. A New Duty Cycle Based Digital Multiplexing Technique Mohamad Khazani Abdullah1, Ghafour ... more Page 1. A New Duty Cycle Based Digital Multiplexing Technique Mohamad Khazani Abdullah1, Ghafour Amouzad Mahdiraji1, Mohamed Faisal Elhag1, Ahmed Fauzi Abas1, Edmond Zahedi2 and Makhfudzah Mokhtar1 1Photonics ...

2013 IEEE 4th International Conference on Photonics (ICP), 2013

ABSTRACT We reported an optimization method to improve Multi Slot Amplitude Coding (MSAC) optical... more ABSTRACT We reported an optimization method to improve Multi Slot Amplitude Coding (MSAC) optical fiber system performance. Simulation result clearly shows that optimum back to back BER performance is achieved when signal level spacing for upper level is higher than that of the lower level in order to compensate the signal dependent noise. In addition, we compare optimized system performance in terms of optical received power (ORP), optical signal to noise ratio (OSNR) and chromatic dispersion (CD) tolerance with conventional MSAC method. Improvement of 4.5 dB in ORP and OSNR are observed.

Optics Communications, 2004

In this paper, we demonstrate a new architecture of multi-wavelength Brillouin/Erbium fibre laser... more In this paper, we demonstrate a new architecture of multi-wavelength Brillouin/Erbium fibre laser in a linear cavity. The architecture utilised a bi-directional oscillation provided by two fibre loop mirrors at both ends of the laser cavity. The efficiency of bi-directional amplification in the Erbium-doped fibre exhibited a low threshold operation of 5.5 mW pump power of 980 nm to create the first Brillouin Stokes. A stable operation of eighteen Brillouin Stokes with 10.88 GHz spacing was obtained at around 1558 nm band.

Optics Communications, 1999

Erbium-doped fibre ring laser is modelled, incorporating the effects of ion pairs, using the prop... more Erbium-doped fibre ring laser is modelled, incorporating the effects of ion pairs, using the propagation and rate equations of a homogeneous, two-level medium. The numerical model has been obtained by developing a spectral analysis of erbium-doped fibre amplifiers. This approach is modified to account for the cyclical propagation of the field in the ring laser. Numerical simulations provide interesting information on the spectral behaviour as well as important parameters for device analysis and design, mainly the lasing wavelength and output power.

Optical Engineering, 2006

An optical dynamic spectral encoding code division multiple access ͑CDMA͒ communication system is... more An optical dynamic spectral encoding code division multiple access ͑CDMA͒ communication system is proposed. In this system, an electrically controlled tunable optical filter ͑TOF͒ is used to encode the modulated broadband light source. The code depends on the function set to the controller. Two-dimensional code, named functional code, is also proposed based on a shifted sine function. The function defines the dynamic coding pattern of the central wavelength of the transmitted narrowband optical signal. Thus, the system will allow for an easy reconfiguration of the transmitter without the need for a sophisticated encoder. At the receiver, a synchronized TOF with the same function is used as a decoder. The system is modeled and analyzed taking into account the multiple access interference, phase-induced intensity noise ͑PIIN͒, and thermal noise. The performance of this system is shown to be better compared with a fast frequency hopping ͑FFH͒ system and a spectral amplitude coding ͑SAC͒ system that uses either a Hadamard code, a modified quadratic congruence ͑MQC͒ code, or a modified frequency hopping ͑MFH͒ code.

Microwave and Optical Technology Letters, 2006

A new architecture of dual-stage erbium-doped fiber amplifier with double-pass preamplification i... more A new architecture of dual-stage erbium-doped fiber amplifier with double-pass preamplification is successfully demonstrated. A maximum gain of 52 dB is obtained at Ϫ50-dBm signal power with 1550-nm signal wavelength. An efficient filtering of amplified spontaneous emission improves gain at the signal wavelength up to 18 dB in the double-pass amplifier section. The noise-figure penalty is very minimal in the small-signal range, compared to the dual-stage amplifier without bandpass filters.

Laser Physics, 2008

We present a high-gain erbium-doped fiber amplifier to be utilized as a preamplifier. A double-pa... more We present a high-gain erbium-doped fiber amplifier to be utilized as a preamplifier. A double-pass amplification technique is used in the first-stage amplifier together with a tunable bandpass filter. The secondstage amplifier is a counter-pumped configuration and another tunable bandpass filter is utilized to filter out amplified spontaneous emission from the firststage amplifier. This design is able to produce a high gain of 55.6 dB and a noise figure of 6.02 dB at 1530 nm with a signal power of −45 dBm. The receiver sensitivity measurement shows that the proposed amplifier improves the minimum detectable power from −33.7 to −40.8 dBm for a bit-error rate of 10−11 at 155 Mbps.

Journal of Nonlinear Optical Physics & Materials, 2000

Dual-cavity Brillouin/erbium fiber laser demonstrate a multiwavelength output in a cavity compris... more Dual-cavity Brillouin/erbium fiber laser demonstrate a multiwavelength output in a cavity comprises of nonlinear Brillouin gain and linear EDF gain. The system consists of two erbium-doped fiber lasers EDFL sharing a single mode fiber to produce bidirectional Stokes signals. One of the cavities was made to incur a higher cavity loss and this results in a wavelength-shift of the EDF peak gain. The cavity coupling leads to a slightly broader EDF peak gain and hence increases the number of Stokes lines. The dual-cavity BEFL generates an output of 22 GHz-comb 2×15-channels at 1560 nm that can be used for DWDM system.

Japanese Journal of Applied Physics, 2009

Performance of 3× 10 Gbps duty-cycle division multiplexing (DCDM) is analyzed. The channel demult... more Performance of 3× 10 Gbps duty-cycle division multiplexing (DCDM) is analyzed. The channel demultiplexing is performed electronically at single user bit rate (10 Gbps). At 30 Gbps, null-to-null spectral width of 80 GHz is measured for DCDM technique which is 33.3% less compared to 30 Gbps conventional return-to-zero (RZ). In this system, the worst channel required a receiver sensitivity of

International journal of ophthalmology, 2016

The effect of self-phase modulation (SPM) on 40 Gb/s absolute polar duty cycle division multiplex... more The effect of self-phase modulation (SPM) on 40 Gb/s absolute polar duty cycle division multiplexing (AP-DCDM) is investigated and reported. The study includes the influence of launched power, number of channels and dispersion compensation method. Dispersion post-compensation and combination of dispersion pre- and post-compensation are used to manage the transmission links. At high powers, SPM degrades the pulse recompression process and provides an upper bound on the AP-DCDM transmitted pulse energy. It is demonstrated that the 40 Gb/s AP-DCDM system shows a 4.1 dB improvement and less than 1 dB penalty in terms of SPM tolerance in comparison to 40 Gb/s 4-ary and on – off-keying (OOK) systems, respectively. The SPM effect is stronger in the 100% post-compensated link than that in the combination of pre- and post-compensated links. Dispersion pre-compensation of 18–22% is found as the optimum range of pre-compensation ratio for AP-DCDM system, which makes optimisation of the launche...

2005 13th IEEE International Conference on Networks Jointly held with the 2005 IEEE 7th Malaysia International Conf on Communic

... Monir Abdullah, Mohamed Othman and Rozita Johari Department of Communication Technology and N... more ... Monir Abdullah, Mohamed Othman and Rozita Johari Department of Communication Technology and Network Faculty of Computer Science and Information Technology Universiti Putra Malaysia,Serdang, Selangor, Malaysia monabdullah ... [6] C. Qiao, R. Melhem, D. Chiarulli ...

2008 6th National Conference on Telecommunication Technologies and 2008 2nd Malaysia Conference on Photonics, 2008

A new multiplexing technique based on duty cycle division is proposed, thus the name duty cycle d... more A new multiplexing technique based on duty cycle division is proposed, thus the name duty cycle division multiplexing (DCDM). DCDM can be applied in both electrical and optical domains, for wired and wireless systems. The new technique allows for more efficient use of time slots as well as the spectrum, taking advantage of both the conventional TDM and FDM. In this paper, three channels operating at the same speed of 10 Gbps per channel are multiplexed in the electrical domain. The performance comparison is made against 3times10 Gbps TDM, and the experimental simulation results show that the DCDM system can support higher bit rate than TDM and also, it is less sensitive to the chromatic dispersion effect.

9th Asia-Pacific Conference on Communications (IEEE Cat. No.03EX732)

Increasing the bandwidth until the physical limit of the optical medium itself (fiber optics) has... more Increasing the bandwidth until the physical limit of the optical medium itself (fiber optics) has always been the striving goal in designing an optical fiber communication system. Wavelength division multiplexing (WDM) and its dense version (DWDM) are widely accepted as the best approaches thus far. In this paper, a study on the sub-carrier multiplexing at radio frequency (RF) bands is proposed as a complementary technique to increase the transmission bandwidth. Two channels (each at 155 Mbps rate) and eight channels (each at 622 Mbps rate) of pseudo-random bit sequence of the NRZ-encoded data were tested. The channels were sub-carried by two RF signals at 500 MHz and 1 GHz respectively, while the eight channels system were sub-carried by 1 GHz, 2 GHz, 3 GHz and 4 GHz over each of the two wavelengths. The simulations were carried out over a fiber distance of 70 km. The effect of transmission native rate on the selection of the sub-carrier frequency is also presented.

2008 6th National Conference on Telecommunication Technologies and 2008 2nd Malaysia Conference on Photonics, 2008

In this study the author has modeled and characterizes the performance of 3times10 Gbp/s absolute... more In this study the author has modeled and characterizes the performance of 3times10 Gbp/s absolute polar duty cycle division (APDCDM) multiplexing in dispersive environments at 1550 nm. APDCDM technique is examined, with comparison to non-return-to-zero (NRZ) and return-to-zero (RZ) time division multiplexing. In this paper three channel operating at the same speed of 10 Gbps are multiplexed in electrical domain. The experimental simulation results show that the receiver sensitivity of all users in APDCDM system is similar to that of RZ-TDM and 3 dB better than NRZ-TDM. The proposed system offer reduced dispersion sensitivity; this suggests advantages for APDCDM in optical multiplexing systems. It was also showed that APDCDM can support higher bit rate than TDM and also, it is less sensitive to the chromatic dispersion effect.

2008 6th National Conference on Telecommunication Technologies and 2008 2nd Malaysia Conference on Photonics, 2008

The authors propose a new multiplexing and demultiplexing technique based on return-tozero (RZ) d... more The authors propose a new multiplexing and demultiplexing technique based on return-tozero (RZ) duty cycle division, which is called absolute polar duty cycle division multiplexing (APDCDM). The new technique allows for more efficient use of time slots as well as spectrum. In this paper three users operating at the same speed of 2.5 Gb/s are multiplexed in electrical domain. The performance comparison is made against 7.5 Gb/s return-to-zero time division multiplexing (TDM) system. The experimental simulation results show that although APDCDM has the same receiver sensitivity as TDM but it is able to support higher distance and higher bit rate than TDM.

2008 6th National Conference on Telecommunication Technologies and 2008 2nd Malaysia Conference on Photonics, 2008

In is paper, the maximum power per chip to keep the Stimulated Raman Scattering (SRS)induced tilt... more In is paper, the maximum power per chip to keep the Stimulated Raman Scattering (SRS)induced tilt below a specific level in Spectral-Amplitude-Coding Optical Code-Division Multiple-Access (SAC-OCDMA) is evaluated for different number of users. A number of computer simulations have been conducted for this purpose. It is shown that as number of users grows, the power per chip must be decreased to control the SRS-induced tilt and to keep it below acceptable levels. It is also shown that SRS-induced tilt can significantly limit the power per chip levels when the number of users is large. This is the first time such a study is reported for OCDMA systems.

TENCON 2005 - 2005 IEEE Region 10 Conference, 2005

Abstract-Investigation of L-band linear cavity multiwavelength Brillouin-Erbium fiber laser sourc... more Abstract-Investigation of L-band linear cavity multiwavelength Brillouin-Erbium fiber laser source has been experimentally studied. The effects of Brillouin pump power and wavelength on the threshold pump power are discussed in the paper. We found that there is a limited range ...

ICSE'98. 1998 IEEE International Conference on Semiconductor Electronics. Proceedings (Cat. No.98EX187)

Page 1. ICSE'98 Proc., Nov. 1998, Bangi, Malaysia 105 TAPPER RATIO DEPEN... more Page 1. ICSE'98 Proc., Nov. 1998, Bangi, Malaysia 105 TAPPER RATIO DEPENDENCY OF A LOW-COST PASSIVE OADM SYSTEM Ruzita Abu Bakar*, Mohamad Khazani Abdullah, Fazlee Isnin, Harith Ahmad, and Burhanuddin ...

2006 2nd International Conference on Information & Communication Technologies

Abstract Cognitive radio (CR) is an emerging approach for a more efficient usage of the precious ... more Abstract Cognitive radio (CR) is an emerging approach for a more efficient usage of the precious radio spectrum resources, which it considers an expanded view of the wireless channel by managing and adapting various dimensions of time, frequency, space, power, ...

2007 IEEE International Conference on Telecommunications and Malaysia International Conference on Communications, 2007

Page 1. A New Duty Cycle Based Digital Multiplexing Technique Mohamad Khazani Abdullah1, Ghafour ... more Page 1. A New Duty Cycle Based Digital Multiplexing Technique Mohamad Khazani Abdullah1, Ghafour Amouzad Mahdiraji1, Mohamed Faisal Elhag1, Ahmed Fauzi Abas1, Edmond Zahedi2 and Makhfudzah Mokhtar1 1Photonics ...

2013 IEEE 4th International Conference on Photonics (ICP), 2013

ABSTRACT We reported an optimization method to improve Multi Slot Amplitude Coding (MSAC) optical... more ABSTRACT We reported an optimization method to improve Multi Slot Amplitude Coding (MSAC) optical fiber system performance. Simulation result clearly shows that optimum back to back BER performance is achieved when signal level spacing for upper level is higher than that of the lower level in order to compensate the signal dependent noise. In addition, we compare optimized system performance in terms of optical received power (ORP), optical signal to noise ratio (OSNR) and chromatic dispersion (CD) tolerance with conventional MSAC method. Improvement of 4.5 dB in ORP and OSNR are observed.

Optics Communications, 2004

In this paper, we demonstrate a new architecture of multi-wavelength Brillouin/Erbium fibre laser... more In this paper, we demonstrate a new architecture of multi-wavelength Brillouin/Erbium fibre laser in a linear cavity. The architecture utilised a bi-directional oscillation provided by two fibre loop mirrors at both ends of the laser cavity. The efficiency of bi-directional amplification in the Erbium-doped fibre exhibited a low threshold operation of 5.5 mW pump power of 980 nm to create the first Brillouin Stokes. A stable operation of eighteen Brillouin Stokes with 10.88 GHz spacing was obtained at around 1558 nm band.

Optics Communications, 1999

Erbium-doped fibre ring laser is modelled, incorporating the effects of ion pairs, using the prop... more Erbium-doped fibre ring laser is modelled, incorporating the effects of ion pairs, using the propagation and rate equations of a homogeneous, two-level medium. The numerical model has been obtained by developing a spectral analysis of erbium-doped fibre amplifiers. This approach is modified to account for the cyclical propagation of the field in the ring laser. Numerical simulations provide interesting information on the spectral behaviour as well as important parameters for device analysis and design, mainly the lasing wavelength and output power.

Optical Engineering, 2006

An optical dynamic spectral encoding code division multiple access ͑CDMA͒ communication system is... more An optical dynamic spectral encoding code division multiple access ͑CDMA͒ communication system is proposed. In this system, an electrically controlled tunable optical filter ͑TOF͒ is used to encode the modulated broadband light source. The code depends on the function set to the controller. Two-dimensional code, named functional code, is also proposed based on a shifted sine function. The function defines the dynamic coding pattern of the central wavelength of the transmitted narrowband optical signal. Thus, the system will allow for an easy reconfiguration of the transmitter without the need for a sophisticated encoder. At the receiver, a synchronized TOF with the same function is used as a decoder. The system is modeled and analyzed taking into account the multiple access interference, phase-induced intensity noise ͑PIIN͒, and thermal noise. The performance of this system is shown to be better compared with a fast frequency hopping ͑FFH͒ system and a spectral amplitude coding ͑SAC͒ system that uses either a Hadamard code, a modified quadratic congruence ͑MQC͒ code, or a modified frequency hopping ͑MFH͒ code.

Microwave and Optical Technology Letters, 2006

A new architecture of dual-stage erbium-doped fiber amplifier with double-pass preamplification i... more A new architecture of dual-stage erbium-doped fiber amplifier with double-pass preamplification is successfully demonstrated. A maximum gain of 52 dB is obtained at Ϫ50-dBm signal power with 1550-nm signal wavelength. An efficient filtering of amplified spontaneous emission improves gain at the signal wavelength up to 18 dB in the double-pass amplifier section. The noise-figure penalty is very minimal in the small-signal range, compared to the dual-stage amplifier without bandpass filters.

Laser Physics, 2008

We present a high-gain erbium-doped fiber amplifier to be utilized as a preamplifier. A double-pa... more We present a high-gain erbium-doped fiber amplifier to be utilized as a preamplifier. A double-pass amplification technique is used in the first-stage amplifier together with a tunable bandpass filter. The secondstage amplifier is a counter-pumped configuration and another tunable bandpass filter is utilized to filter out amplified spontaneous emission from the firststage amplifier. This design is able to produce a high gain of 55.6 dB and a noise figure of 6.02 dB at 1530 nm with a signal power of −45 dBm. The receiver sensitivity measurement shows that the proposed amplifier improves the minimum detectable power from −33.7 to −40.8 dBm for a bit-error rate of 10−11 at 155 Mbps.

Journal of Nonlinear Optical Physics & Materials, 2000

Dual-cavity Brillouin/erbium fiber laser demonstrate a multiwavelength output in a cavity compris... more Dual-cavity Brillouin/erbium fiber laser demonstrate a multiwavelength output in a cavity comprises of nonlinear Brillouin gain and linear EDF gain. The system consists of two erbium-doped fiber lasers EDFL sharing a single mode fiber to produce bidirectional Stokes signals. One of the cavities was made to incur a higher cavity loss and this results in a wavelength-shift of the EDF peak gain. The cavity coupling leads to a slightly broader EDF peak gain and hence increases the number of Stokes lines. The dual-cavity BEFL generates an output of 22 GHz-comb 2×15-channels at 1560 nm that can be used for DWDM system.

Japanese Journal of Applied Physics, 2009

Performance of 3× 10 Gbps duty-cycle division multiplexing (DCDM) is analyzed. The channel demult... more Performance of 3× 10 Gbps duty-cycle division multiplexing (DCDM) is analyzed. The channel demultiplexing is performed electronically at single user bit rate (10 Gbps). At 30 Gbps, null-to-null spectral width of 80 GHz is measured for DCDM technique which is 33.3% less compared to 30 Gbps conventional return-to-zero (RZ). In this system, the worst channel required a receiver sensitivity of