All Optical Two Channel PSK Communication

IEEE Photonics Technology Letters, 2004

We propose a novel transmitter structure to generate constant-intensity wavelength shift keying signal based on optical phase modulation and demonstrate its application in a wavelengthdivision-multiplexed passive optical network to facilitate upstream data remodulation. The feasibility and system performance are experimentally investigated.

Coherent optical fiber communications for data rates of 100 Gbit/s and beyond have recently been studied extensively because high sensitivity of coherent receivers could extend the transmission distance. Spectrally efficient modulation techniques such as M-ary phase shift keying (PSK) can be employed for coherent optical links. The integration of mul-ti-level modulation formats based on coherent technologies with wavelength-division multiplexed (WDM) systems is vital to meet the aggregate bandwidth demand. This paper reviews coherent quadrature PSK (QPSK) systems to scale the network capacity and maximum reach of coherent optical communication systems to accommodate traffic growth.

2007

SUMMARY In this paper we introduce the dual-header pulse interval modulation (DH-PIM) technique employing a simple retransmission coupled with a majority decision detection scheme at the receiver. We analytically investigate the slot error rate (SER) performance and compare results with simulated data for the symbol retransmissions rates of three, four and five, showing a good agreement. We demonstrate that the proposed scheme significantly reduces the SER compared with the standard single symbol transmission system, with ...

IEEE Journal of Selected Topics in Quantum Electronics, 2004

Differential phase-shift keying (DPSK) has attracted significant attentions in research and development during the last several years. An overview of DPSK for high spectral efficiency optical transmission is presented in this paper. The advantages of DPSK in terms of receiver sensitivity and tolerance to fiber nonlinearity will be discussed in detail. A simplified method for estimating the performance of phase-shift keying in numerical simulations is explained. Results of experimental and numerical investigations of several phase shift keying formats, including polarization division multiplexing and multilevel encoding, will be reviewed. Finally, methods for further enhancing performance of phase-shift keying in long-haul transmissions, specifically the compensation of nonlinear phase jitter, are presented.

Journal of Optical Communications, 1999

For an optical homodyne receiver comprising a Costas loop a formula for the phase error variance determining is derived more precisely than even before. The requirement laser linewidth to achieve the bit-error rate 10~1 0 is obtained for the optimally chosen power splitting ratio. Two type of optical PSK homodyne communication systems are taken into consideration: the Costastype receivers and the DDL ones. It is shown that the requirement laser linewidth are less stringent when power splitting ratio is optimally chosen than that for the fixed power splitting ratio obtained starting from the permissible power penalty due to the power splitting.

Journal of Lightwave Technology, 2000

The recently introduced multichip differential phaseshift keying (MC-DPSK) optical transmission format, entailing the modulation of relative phases over a moving transmission window of D successive chip intervals, is analytically and numerically analyzed. The maximum-likelihood optimal MC-DPSK receiver is derived and synthesized using integrated-optic Mach-Zehnder delay interferometers, whose electrical outputs are interpreted as generalized Stokes' parameters. The MC-DPSK performance over a nonlinear fiber channel, limited by the combination of amplified spontaneous emission noise and self-phase modulation, is further derived and simulated, demonstrating that the lowest complexity three-chip binary-phase MC-DPSK receiver provides an ∼1-dB Q-factor advantage over conventional DPSK.

IEEE Transactions on Communications, 1995

The application of the well-known technique of Trellis Coded Modulation t o coherent optical communications using Polarization Shift Keying (POLSK) is described and analyzed. The resulting receiver is formed by a frontend which performs the heterodyne detection and the Stokes parameter extraction, cascaded with an electronic Viterbi processor operating the maximum likelihood estimate of the transmitted sequence. Results in terms of the error event probability using optimum as well as a simpler suboptimum branch metric show power gains on the order of 3-4 dB, at the expense of a reasonable increase in complexity, only concerning the processing in the electronic domain. These coding gains are not lost even in the presence of high levels of phase noise, to which POLSK in general is highly insensitive.

Optics express, 2011

Quadrature phase-shift keying (QPSK) is usually generated using an in-phase/quadrature (IQ) modulator in a balanced driving-condition, showing a square-shape constellation in complex plane. This conventional QPSK is referred to as square QPSK (S-QPSK) in this paper. On the other hand, when an IQ modulator is driven in an un-balanced manner with different amplitudes in in-phase (I) and quadrature (Q) branches, a rectangular QPSK (R-QPSK) could be synthesized. The concept of R-QPSK is proposed for the first time and applied to optical eight-ary phase-shift keying (8PSK) transmitter. By cascading an S-QPSK and an R-QPSK, an optical 8PSK could be synthesized. The transmitter configuration is based on two cascaded IQ modulators, which also could be used to generate other advanced multi-level formats like quadrature amplitude modulation (QAM) when different driving and bias conditions are applied. Therefore, the proposed transmitter structure has potential to be deployed as a versatile tr...

This paper propose Free Space Optics Systems (FSO) which is considers one of the most effective solutions to the optical communication environment.0.00, especially for atmospheric turbulence due to the weather and environment structure. Free space optics system suffers from various limitations. The main objective of this article is to modulate the transmitted signal by using Digital Phase Shift Keying (DPSK) modulation technique at 33% of modulation signal. CW laser input source with wavelength at 1550 nm, power 10mw.Free Space Optic (FSO) used as a media transmission line produces less effect in atmospheric attenuation. Short link range between the transmitter and receiver can optimize the FSO system transmission parameters or components. Based on the analysis, it is recommended to develop an FSO system of 40 Gbps with 1550 nm wavelength and link range up to 700 km .the implementation of this system requiring anew design of OCDMA technique to avoid the suffering system from the problem of multiple access interference (MAI). And then we can achieve an Optical Code Division Multiplexer (OCDMA) system asynchronous transmission, secure communication, of capacity on demand, and high degree of scalability.

Journal of Lightwave Technology, 1991

In this paper the first homodyne receiver for polarization modulated optical signals is proposed and analyzed. It is based on the detection at the receiver of the four quadratures that completely characterize the received optical field and on the estimation of the Stokes parameters starting from them. This allows homodyne detection to be carried out without phase locking the local oscillator (LO) to the received signal. Even if in this paper a binary antipodal polarization modulation homodyne system is analyzed in detail, such a receiver scheme can be implemented for baseband detection of all the kinds of polarization modulated systems. Insensitiveness to polarization fluctuations can be achieved by using electronic algorithms similar to those used in the heterodyne receivers and immunity to phase noise as high as that of all the polarization modulated systems is maintained. For this properties the proposed receiver scheme seems to be attractive for application in high-speed FDM optical networks in which an efficient exploitation of the receiver front end bandwidth and a good immunity to phase noise and polarization fluctuations are important issues.