ABSTRACT
A novel dual-loop optoelectronic oscillator (OEO) based on self-polarization-stabilization technique has been experimentally demonstrated. The input light in each loop will retrace its path through a 45° Faraday rotator and single mode fiber with different length after reflecting off a 45° Faraday rotator mirror. By this way, the polarization state of the output signal is always rotated by 180° from the polarization state of the input signal in each loop even if the round-trip fiber is perturbed by the mechanical vibration or temperature. Moreover, the required fiber length is cut in half due to the round-trip transmission in each path, resulting in higher system stability and more compacter structure. The experimental results show that in an intensity modulator (IM)-based OEO system, this scheme has better phase noise performance than the traditional polarization multiplexing method. Furthermore, to avoid the DC bias drifting problem of IM, a simple phase modulation to intensity modulation convertor by using a polarization-dependent phase modulator and a polarizer is proposed without the need of expensive optical filters or dispersive devices. Based on this scheme, a novel dual-loop OEO using phase modulator and self-polarization-stabilization technique has been experimentally demonstrated. The phase noise of -114.1 dBc/Hz at 10 kHz away from the carrier (10 GHz) is achieved and the side mode suppression ratio is improved to 63 dB.
ABSTRACT
We experimentally demonstrate amplification of 1.28 Tb/s DWDM channels using a bidirectional fiber optical parametric amplifier. The amplifier can provide more than 13 dB on-off gain on all 32 DWDM channels. Error-free operation has been achieved for all data streams, with an average power penalty of 2.5 dB compared with conventional unidirectional configuration.
ABSTRACT
We demonstrate reduction of four-wave mixing crosstalk using hybrid optical parametric amplifier with erbium-doped fiber amplifier. Crosstalk reduction of more than 13 dB has been achieved while providing 20-dB gain. Noise figures of different amplifier configurations are compared. Bit error rate measurements confirm the hybrid configuration introduces < 0.5 dB and < 1.5 dB power penalties in signal and idler wavelength, respectively, compared with a pure optical parametric amplifier.
ABSTRACT
We experimentally demonstrate a demodulation scheme for 20 Gbaud/s nonreturn-to-zero differential quadrature phase-shift keying signals using a silicon microring resonator. Either the I or Q channel can be selected by electrical tuning using the carrier depletion effect. Error-free (bit error rate <10(-9)) operations can be achieved for both the I and Q channels with ~1.5 dB power penalty compared with a commercial 20 GHz Mach-Zehnder delay interferometer. The tuning range of the ring resonator can be up to 60 GHz, which enables operation over a wide range of data rates.
ABSTRACT
We propose a scheme to generate ultrawideband (UWB) monocycle pulses using delayed interference of a π/2 phase-shift keying (PSK) signal. The PSK signal is generated with an optical phase modulator. A fiber-based delay interferometer is used to provide the delay together with a ±π/2 phase shift between the signals in its two arms before the interference. The two opposite phase shifts correspond to the generation of a pair of polarity-reversed UWB monocycle pulses. The full width at half maximum of the pulses is ~68 ps and the 10 dB fractional bandwidth is 168%.
ABSTRACT
We demonstrate a unique solution to use a one-pulse control to achieve simultaneous two-channel all-optical demultiplexing that usually requires a two-pulse control or a two-step operation based on the conventional approaches. By applying a dispersion asymmetric nonlinear optical loop mirror (DA-NOLM) to introduce cross phase modulation (XPM) in both the clockwise (CW) and the counter clockwise (CCW) propagating branches, we have demonstrated reconfigurable, error-free 40-to-10 Gb/s two-channel demultiplexing (DEMUX) for OTDM OOK signals. Switchable operation between two-channel and single-channel DEMUX is also realized based on the proposed all-optical DEMUX configuration.
ABSTRACT
We demonstrate a novel fiber-based in-line DPSK demodulator using an in-fiber Mach-Zehnder interferometer (MZI). The device is fabricated by mismatch splicing of a photonic crystal fiber (PCF) with standard single mode fibers. The spectral characteristics at different PCF lengths are analyzed. The envelope of the interference fringes show a period that is inversely proportional to the PCF length, and is attributed to the periodic coupling between the core mode and the cladding mode. Error free demodulations of 10-Gb/s RZ- and NRZ-DPSK signals have been demonstrated using the in-fiber PCF-MZI demodulator with only 3-m PCF to introduce 91-ps delay. Wideband DPSK demodulation has also been achieved.
