Kamaljit Singh Bhatia

Monitoring and Compensation of Optical Telecommunication Channels by using Optical Add Drop Multiplexers for Optical OFDM System

Abstract This paper forces on the monitoring and compensation of optical telecommunication channels by using Optical add drop multiplexers (OADM) in an Optical orthogonal frequency division multiplexing (OOFDM) system. An adaptive fiber nonlinearity precompensation (AFNP) scheme is also proposed to solve the fiber nonlinearity in coherent optical orthogonal frequency division multiplexed networks (CO-OFDM). Optical performance monitoring (OPM) at end-terminals is applied to channel identification in this paper. It is considered to be high efficiency and a cost efficient technique in low-dynamic system.

Performance Analysis of 16 Channel WDM System with 4 OADM

Abstract In this paper, we presented the wavelength division multiplexing (WDM) system based on optical add-drop multiplexer (OADM). We analysed the effect of loss on Q factor and BER for different fiber lengths. The NRZ modulation format is used for transmitting the signal for 9.953-Gb/s 16-channel WDM system based on OADM.

Suppress the FWM by Increasing Channel Spacing and Chromatic Dispersion of Fiber in WDM System

Abstract In this paper, we investigate the effect of channel spacing and chromatic dispersion on four wave mixing in WDM system. Dominating effect of four wave mixing is minimizing at maximum value of dispersion and channel spacing. Power of FWM, Q-factor, bit error rate and output spectrum is used to measure the performance of system.

Impact of Initial Laser Phase Values on Soliton Transmission

Abstract In this paper we demonstrated the variation of different parameterswith initial laser phase values of optical pulse generator which generates solitons, in soliton transmission and analyzed that how the difference of these two initial laser phase values effects Q-values.

CATV Transmission in Optical Communication System

Abstract In this paper we analyze analog CATV transmission system where only one wavelength is used for transmission on which multiple analog RF channels modulated. We analyze different modulation distortions such as composite second order (CSO), composite triple beat (CTB) and intermodulation distortions at different frequencies. Good performance of CSO > −36 dBc and CTB > −41 dBc are obtained at 62.5 MHz, 125 MHz and 187.5 MHz in three tone directly modulated CATV transmission system.

Authenticating Mobile Phone Users Based on Their Typing Position Using Keystroke Dynamics

Keystroke dynamics is an emerging biometric method for user authentication. With the increased use of mobile phones, the use of keystroke dynamics for mobiles has been evaluated by many researchers. Mostly, the research has been carried upon data which was collected from users when they were in sitting position only. This study was conducted by collecting user data in two positions, sitting and walking, and using the phone in landscape and portrait mode. The results were positive with best EER of 3.69% achieved in walking-landscape position by using standard keystroke features and random forest algorithm. The results were also better as compared to making a single user profile by combining the data from all different positions where the achieved EER was 4.12%.

Analysis of secured Optical Orthogonal Frequency Division Multiplexed System

Abstract In this paper, security issues for optical orthogonal frequency division multiplexed (OFDM) systems are emphasized. The encryption has been done on the data of coded OFDM symbols using data encryption standard (DES) algorithm before transmitting through the fiber. The results obtained justify that the DES provides better security to the input data without further bandwidth requirement. The data is transmitted to a distance of 1,000 km in a single-mode fiber with 16-quadrature amplitude modulation. The peak-to-average power ratio and optical signal-to-noise ratio of secure coded OFDM signal is fairly better than the conventional OFDM signal.

Analyzing DWDM System with Different Modulation Formats and Channel Spacing

Abstract Different modulation formats for 64×20-GB/s dense wavelength division multiplexed (DWDM) system has been compared and simulated using Optsim. Various performance parameters including Q-factor, bit error rate, jitter, eye opening & eye closure are observed and analyzed. It is reported that RZ Soliton format is a better choice among the tested formats. Also, for the proposed system, minimum channel spacing should be 50 GHz.

Investigations of Different Amplifiers in 16 × 40 Gb/S WDM System

Abstract Different fiber amplifiers such as semiconductor optical amplifier, erbium-doped fiber amplifier and erbium ytterbium-co-doped fiber amplifier (EYCDFA) are investigated for 16×40 GB/s wavelength division multiplexing system. Various performance parameters including Q-factor, bit error rate, jitter, eye opening and eye closure are observed and analyzed. It is reported that EYCDFA is a better choice among the tested amplifiers. The proposed system is also investigated in terms of transmission distance.

Combating/eliminating dispersion-induced fading using suppressed carrier link for OFDM signal

ABSTRACT We investigate the performance of 20-GHz radio over fibre (RoF) system having orthogonal frequency division multiplexed (OFDM) as radio signal using two modulation techniques – balanced detection for intensity modulation direct detection (IMDD) and coherent heterodyne detection suppressed carrier (SC) modulation. Dispersion-induced power fading is seen in conventional IMDD links due to the dependence of dispersion over frequency-dependent refractive index of the fibre. SC link is seen to compensate the power fading by terminating the direct current and even-order harmonics with the suppression of carrier along with balanced detection.