A Silicon-on-Insulator (SOI) Differential Quadrature Phase Shift Keying (DQPSK) demodulator based on a novel Multimode Interference (MMI) design is characterized for a number of operating wavelengths, with results indicating good uniformity and low wavelength dependency. Keywordssilicon integrated devices; DQPSK demodulator; MMI; characterization

This paper investigates the effect of chip waveform shaping on the error performance, bandwidth confinement, phase continuity, and envelope uniformity in direct-sequence codedivision multiple-access communication systems employing offset quadrature modulation formats. An optimal design methodology is developed for the problem of minimizing the multipleaccess interference power under various des...

In electronic digital signal processing based optical communication systems, digital equalization for chromatic dispersion interacts with local oscillator phase noise to produce equalization-enhanced phase noise (EEPN). In addition to both phase and intensity noises, EEPN also induces timing jitter to the equalized signal. For a 100 Gbit/s quadrature-phase-shift keying signal with laser linewid...

Jaeyoon Lee et al. 707 In-phase/quadrature (I/Q) imbalances, which are generated by non-ideal transceiver components, are inevitable physical phenomena that cause the performance of practical communication systems to be degraded. In this paper, we provide a new closed-form expression for the bit error rate of hierarchical M-ary phase shift keying with I/Q phase and amplitude imbalances and anal...

We report multicasting data from a single orbital angular momentum (OAM) spatial channel onto multiple OAM channels of equally spaced OAM charge numbers. The designed sliced phase patterns for multicasting are loaded on the spatial light modulator. By optimizing the design of the phase pattern, the power of multicasted OAM channels can be equalized. We experimentally demonstrate multicasting fi...

In this work, the performance of two equalizers Least Mean Square (LMS) and Recursive Least Square (RLS) is observed by calculating the BER effect of Rician channels over low Doppler shift. AWGN is also added to the channel from -10 dB to 20 dB. The Bit Error Rate (BER) of 2, 4, 8-PSK (Phase Shift Keying) signals and 16, 64QAM (Quadrature Amplitude Modulation) over Rayleigh and Rician channel i...

This paper proposes a Quadrature Phase Shift Keying (QPSK) using two different methods. QPSK is one of the forms of Phase Shift Keying (PSK) modulation scheme. Generally a conventional QPSK modulator with Direct Digital Synthesizer (DDS) and arithmetic multiplier separates base band signal into I and Q phase which consumes low throughput with complexity in hardware implementation. Hence to gene...

A phase-sensitive four-wave mixing (FWM) scheme enabling the simultaneous conversion of the two orthogonal quadratures of an optical signal to different wavelengths is demonstrated for the first time under dynamic operation using a highly nonlinear optical fiber (HNLF) as the nonlinear medium. The scheme is first optimized with respect to the power levels and phases of the four phase-coherent p...

OFDM is a multicarrier modulation technology which has efficient spectrum utilization to support the transmission of high data rates. The typical subcarrier modulation schemes used in orthogonal frequency division multiplexing (OFDM) system includes: b inary phase shift keying (BPSK), phase shift keying (PSK) and quadrature amplitude modulation (QAM). This paper analyses the comparative perform...

Modulation techniques have concerned increasing attention in optical wireless communications. Downlink transmission (base station to mobile terminal) using high data rate Mary Quadrature Amplitude Modulation (QAM), Quadrature Phase Shift Keying (QPSK) and Binary Phase Shift Keying (BPSK) modulation schemes are considered in a Wideband-Code Division Multiple Access (W-CDMA) system. QPSK or Quadr...