We report implementation of a monolithically integrated 100 Gbps dual-polarization quadrature phase shift keying (DP-QPSK) wavelength tunable coherent receiver on a 1  mm×3  mm die that consists of a tunable C-Band local oscillator with a 40 nm range, eight 30 GHz photodetectors, and two parallel 90° optical hybrids. A BER of 10(-3) with an OSNR of 7.5 dB operating at 50 Gbps NRZ-QPSK data per ...

A new lock detection algorithm for digital quadrature phase-shift keying (QPSK) receiver is proposed. Analysis of the detector’s output characteristics is given and is verified by using computer simulation. Performance degradation due to carrier jitter is also considered. Analytic and simulation results show that the proposed algorithm is very useful as a lock detector in digital receivers beca...

Using 1-μm InP HBT technology, a transimpedance amplifier (TIA) IC for optical links using 100-Gb/s dual polarization quadrature phase shift keying (100-G DP-QPSK) was designed and fabricated. Its wide dynamic range of 0.2∼2mAppd input current and good linearity of less than 3.3-% total harmonic distortion (THD) were confirmed. Also, externally controllable functions such as output amplitude ad...

Low-density parity-check (LDPC) codes provide capacity approaching performances with very long codes in a coherent channel. However, as the block length increases, their performance becomes worse with residual frequency offsets. Residual frequency offsets can be tackled with sub-block decoding and LDPC code-aided phase ambiguity resolution for binary phaseshift keying (BPSK) signals. Sub-block ...

Quadrature Phase Shift Keying (QPSK) and Offset Quadrature Phase Shift Keying (OQPSK) are two wellaccepted modulation techniques used in Code Division Multiple Access (CDMA) system. The Pulse-Shaping Filters play an important role in digital transmission. The type of Pulse-Shaping Filter used, and its behavior would influence the performance of the communication system. This in turn, would have...

We propose and demonstrate an all-optical phase noise reduction scheme that uses optical nonlinear mixing and tunable optical delays to suppress the low-speed phase noise induced by laser linewidth. By utilizing the phase conjugate copy of the original signal and two narrow-linewidth optical pumps, the phase noise induced by laser linewidth can be reduced by a factor of ∼5 for a laser with 500-...

QPSK or Quadrature Phase-Shift Keying is a higher order modulation scheme used in digital modulation. A direct injection locked QPSK modulator uses VCO for minimize the area of the conventional modulator. In this project injection locking scheme is used since injection locking has an advantage inphase-noise reduction ofoscillators withavery simplecircuittopology. By using proposed simple modula...

Silicon microring resonators are proposed to achieve ultrasmall differential quadrature phase-shift keying modulators and demodulators operated at 20 Gb/s, which may require a dramatically reduced chip size. The modulators are characterized in terms of the carrier transit time and misalignment of the driving signals, while the demodulation performance is analyzed in terms of the bandwidth and f...

We investigate the orthogonality of orbital angular momentum (OAM) with other multiplexing domains and present a free-space data link that uniquely combines OAM-, polarization-, and wavelength-division multiplexing. Specifically, we demonstrate the multiplexing/demultiplexing of 1008 data channels carried on 12 OAM beams, 2 polarizations, and 42 wavelengths. Each channel is encoded with 100 Gbi...