The noise figures (NF) of near-infrared (near-IR) amorphous silicon (a-Si) and mid-infrared (mid-IR) crystalline silicon (c-Si) optical parametric amplifiers (OPA) are numerically investigated. The impact of nonlinear losses, i.e., two-photon absorption (TPA) and TPA-induced free carrier absorption (FCA), as well as Raman-effect-induced complex nonlinear coefficient are taken into account in a-Si OPAs. The amplified spontaneous emission (ASE) of Erbium-doped fiber amplifiers (EDFA) and the relative intensity noise (RIN) of the pump laser are considered as the dominant pump noises when simulating the pump transferred noise (PTN) of near-IR a-Si and mid-IR c-Si OPAs, respectively. It is shown that in typical near-IR a-Si OPAs, the NF is ∼5 dB on the Stokes side but increases sharply to above 10 dB at the gain edge on the anti-Stokes side. In high-gain mid-IR c-Si OPAs, the NF is dominated by the PTN and is well above 10 dB at the gain edge. These results indicate that both near-IR a-Si OPAs and mid-IR c-Si OPAs are promising alternatives to near-IR c-Si OPAs, but they both have limitations in broadband operation.
An exact analytical formulism obtained directly by solving a system of rate and propagation equations in the presence of pump excited-state absorption is presented on the basis of four-band transition scheme in radially symmetric and longitudinally uniform monomode erbium doped silica fiber lasers. The exact analytical expressions are determined for overall gain, small-signal gain, pump intensity threshold, lasing threshold condition, and optimal fiber length in terms of alleviative measurable quantities of photon intensities, transition rates, absorption and emission cross sections, and reflectivity of mirrors. Mutatis mutandis, the formulas bear a verisimilitude to analytical expressions appearing in the literature for these parameters.
In this study, we provide an experimental assessment of a quantum dash Fabry–Pérot mode-locked laser for all-optical clock recovery using data streams at 40, 80, 160, and 320 Gb/s. The data streams at 80, 160, and 320 Gb/s are phase coherent signals featuring no spectral component at 40 GHz. The 40 GHz recovered optical clock signal is characterized in terms of phase noise, timing jitter, dynamic power range, and wavelength dependence for the different data rates. Our experiments demonstrate a recovered optical clock signal from a 320 Gb/s data stream with a timing jitter of 94 fs and wavelength detuned by 23 nm. In addition, the performance of the optical time division multiplexing receiver at 80 and 160 Gb/s data signals employing the recovered clock as a demultiplexing control signal and as a clock for the bit-error-rate tester (BERT) is evaluated by bit error rate measurements on the demultiplexed data signals.
Application of a self-sweeping self-pulsing laser for high-resolution spectral analysis of π-shifted FBGs has been demonstrated for the first time. It is shown that the self-sweeping laser generates nearly single-frequency radiation during a single pulse. This fact allows us to characterize the shift-induced dip of 14 MHz width in the FBG reflection spectrum. Nonlinear deformation of the measured ultranarrow spectral structure with increasing incident power is observed. Sampling interval during the scan is shown to be limited by pulse to pulse frequency shift, which is equal to the cavity mode spacing of 6 MHz. The main feature of the applied technique is its simplicity due to the absence of special elements for frequency scanning.
We experimentally evaluate the performance of incoherent multiple-input multiple-output (MIMO) multimode fiber (MMF) links with different fiber media, link lengths, and modulation techniques. The performance of conventional 62.5
We report on an opto-electronic oscillator (OEO) widely tunable from 2.5 to 5.5 GHz. It is based on an Er,Yb:glass Dual-Frequency Laser operating at 1.53
Here we report the experimental implementation of a linear-optics partial Bell-state analyzer following the propagation of single-photons through long telecommunication optical fibers. Polarization encoded weak coherent states were sent from independent remote continuous wave faint laser sources over two 8.5 km long optical fiber spools. Automatic polarization stabilization systems were used in each spool to compensate the random polarization drift. We demonstrate stable two-photon interference with a dip visibility of 47.8% over a 40 minute time-interval, close to the theoretical maximum of 50% for weak coherent states. We successfully show that it is possible to carry out remote long-distance Bell-state analysis of polarization weak coherent states in spite of random residual birefringence fluctuations in optical fibers. These results pave the way for important applications in quantum communications with polarization qubits such as measurement device-independent quantum key distribution and quantum repeaters.
We demonstrate a new type of optical saturable absorber based on the self-assembled topological insulator Bi
We demonstrate a robust, compact and low-loss four-channel wavelength-division multiplexing (WDM) filter based on cascaded double-ring resonators (2RR) in silicon. The flat-top channel response obtained by the second-order filter design is exploited to compensate for the detrimental effects of local fabrication variations and their associated phase errors on the ring-based filter response. Full wafer-scale characterization of a cascaded, four-channel 2RR filter with channel spacing of 300 GHz shows an average worst-case insertion loss below 1.5 dB and an average worst-case crosstalk below