Simranjit Singh

Flat-Gain L-Band Raman-EDFA Hybrid Optical Amplifier for Dense Wavelength Division Multiplexed System

An efficient gain-flattened L-band optical amplifier is demonstrated using a hybrid configuration with a distributed Raman amplifier (DRA) and an erbium-doped fiber amplifier (EDFA) for 160 × 10-Gb/s dense wavelength division multiplexed system at 25-GHz interval. With an input signal power of 3 mW, a flat gain of >; 10 dB is obtained across the frequency range from 187 to 190.975 THz with a gain variation of <; 4.5 dB without using any gain-flattening technique. The output power obtained at 3-mW optimum input power is also the highest value (>; 8.9 dBm) ever reported for a DRA-EDFA hybrid optical amplifier at reduced channel spacing.

Novel Optical Flat-Gain Hybrid Amplifier for Dense Wavelength Division Multiplexed System

For the first time, a novel flat-gain optical amplifier is proposed using a hybrid configuration with an Er-Yb co-doped waveguide amplifier (EYDWA) and a semiconductor optical amplifier (SOA) for 100 × 10-Gb/s dense wavelength division multiplexed system at 0.2 nm interval. With an EYDWA-SOA hybrid amplifier, a flat gain of is obtained across the effective bandwidth with a gain variation of the order of 0.75 dB without using any gain clamping techniques. It is observed that when the proposed hybrid amplifier is used as a booster for hybrid distributed Raman amplifier and erbium doped fiber amplifier, the gain variation is reduced from 2.01 to ~ 1.15 dB efficiently with acceptable bit error rate.

Investigation of Hybrid Optical Amplifiers for Dense Wavelength Division Multiplexed System with Reduced Spacings at Higher Bit Rates

Abstract This article proposes various combinations of optical amplifiers for a dense wavelength division multiplexed system and investigates the impact of reduced channel spacing at high bit rates in terms of quality factor, bit error rate, eye closure, and output power. It is reported that the hybrid optical amplifier (Raman–erbium-doped fiber amplifier [EDFA]) provides better results with a maximum covered single span distance (220 km) at channel spacing of 6.25 GHz. The maximum acceptable bit rate for the 12.5-GHz channel spacing dense wavelength division multiplexed system is also investigated, and the recommendation is provided that for the Raman–EDFA, Raman–EDFA–Raman, EDFA–Raman–EDFA, and EDFA–semiconductor optical amplifier–EDFA, the operating bit rate should not be greater than 20, 16, 19, and 20 Gbps, respectively.

Photonic processing for all-optical logic gates based on semiconductor optical amplifier

Abstract. All-optical signal processing plays an important role in the development of ultrahigh speed optical networks. All-optical logic schemes, such as OR, AND, NOT, and XOR gates, are projected using semiconductor optical amplifiers. Further, to verify the results of proposed logical gates, the half adder has also been realized and has achieved an accurate performance. The proposed schemes omit the requirement for an optical delay line or costly O-E-O conversions which makes the system flexible.

Performance evaluation of hybrid optical amplifier for high-speed differential phase-shift keying-modulated optical signals

Abstract. The hybrid Raman and erbium-doped fiber amplifier is investigated for a 16×40  Gbps differential phase-shift keying (DPSK) modulation system at different channel spacings. It is reported that the proposed hybrid optical amplifier (HOA) provides better gain, signal quality and induces lesser crosstalk even when 640 Gbps DPSK signals are transmitted over 100 km of pumped single mode fiber. Further, the proposed system performance is compared with the current state-of-the-art HOA schemes.

Multiparameter optimization of a Raman fiber amplifier using a genetic algorithm for an L-band dense wavelength division multiplexed system

Abstract. We present a simple genetic algorithm implemented to perform multiparameter optimization of a Raman fiber amplifier for a 100-channel L-band dense wavelength division multiplexed system at a 25-GHz interval. The system is investigated for various cases with fixed pump frequency leading to 202.2-THz pump as the best choice with average gain above 19.5 dB. There is evidence to show that a single counterpropagating pump optimized to 588.2-mW power level and optimum Raman fiber length of 38.8 km presents a small gain variation (<2  dB) over an effective bandwidth covering 187 to 189.475 THz. The optimized configuration enabled an adequate system performance in terms of acceptable Q-factor (17 dB) and bit error rate (5.60×10−13).

Performance investigation of Raman erbium-doped fiber amplifier hybrid optical amplifier in the scenario of high-speed orthogonal-modulated signals

Abstract. We propose a new optical data format based on simultaneously modulating nonreturn-to-zero and polarization-shift-keying for high-speed applications by means of efficient utilization of bandwidth. To the best of our knowledge, this article reports on the first investigation of a Raman erbium-doped fiber amplifier hybrid optical amplifier using a hybrid/orthogonal modulation technique in the scenario of 8- and 20-channel dense wavelength division multiplexed systems with high-data rates at 0.2 and 0.8 nm channel spacing, respectively. The results show that the proposed modulation format offers significant advantages in offering high-spectral efficiency values with acceptable quality factors and bit error rates.

Review on recent developments in hybrid optical amplifier for dense wavelength division multiplexed system

Abstract. Hybrid optical amplifiers (HOAs) are crucially important for broadband band amplification, and are widely deployed in high-capacity dense wavelength division multiplexed systems. We summarize the present state-of-the-art in this rapidly growing field. In addition, theoretical background and various inline configurations of optical amplifiers have been presented. Various issues such as gain flatness, gain bandwidth, transient effect, and crosstalk were presented in HOAs. Results show that the HOAs provide better gain flatness without using any expensive gain flattening techniques, and an acceptable range of gain, noise figure, bit error rate, and transience.

On the Optimization of Raman Fiber Amplifier using Genetic Algorithm in the Scenario of a 64 nm 320 Channels Dense Wavelength Division Multiplexed System

For multi parameter optimization of Raman Fiber Amplifier (RFA), a simple genetic algorithm is presented in the scenario of a 320 channel Dense Wavelength Division Multiplexed (DWDM) system at channel spacing of 25 GHz. The large average gain (> 22 dB) is observed from optimized RFA with the optimized parameters, such as 39.6 km of Raman length with counter-propagating pumps tuned to 205.5 THz and 211.9 THz at pump powers of 234.3 mW, 677.1 mW respectively. The gain flattening filter (GFF) has also been optimized to further reduce the gain ripple across the frequency range from 190 to 197.975 THz for broadband amplification.

Optimizing the Net Gain of a Raman-EDFA Hybrid Optical Amplifier using a Genetic Algorithm

For the first time, a novel analytical model of the net gain for a Raman-EDFA hybrid optical amplifier (HOA) is proposed and its various parameters optimized using a genetic algorithm. Our method has been shown to be robust in the simultaneous analysis of multiple parameters (Raman length, EDFA length, and pump powers) to obtain large gain. The optimized HOA is further investigated at the system level for the scenario of a 50-channel DWDM system with 0.2-nm channel spacing. With an optimized HOA, a flat gain of >17 dB is obtained over the effective ITU-T wavelength grid with a variation of less than 1.5 dB, without using any gain-flattening technique. The obtained noise figure is also the lowest value ever reported for a Raman-EDFA HOA at reduced channel spacing.