Search

We report on an in-band optical signal-to-noise ratio monitoring technique for wavelength division multiplexed channels. Our proposal relies on the different degree of polarization between the signal (highly polarized) and the noise (not polarized). Using this principle, we divide the signal under test into two orthogonal polarization components and induce a differential group delay via a controlled birefringence apparatus that produces a wavelength-dependent shift of the polarization state of the signal. After a linear polarizing filter, high-resolution spectral analysis allows measurement of the amplified spontaneous emission noise level. The method is tested by experimental measurements of a 40 Gbit/s differential phase-shift keying channel showing very good performance. OCIS codes: 060.0060, 300.6320, 060.2300, 060.4510.

A process for the complete experimental evaluation of the main working parameters for semiconductor lasers applicable to several types of market-available semiconductor lasers is described. The main advantage of the method is that it requires the use of only one setup for all the measurements, thereby making it much faster and easier to automate and could be applied to other types of single-mode semiconductor lasers without further revisions.

In this paper, we study the use of integrated semiconductor optical amplifiers as the basic building block for larger-scale programmable photonic circuits. Making use of the non-linear response of these devices, we study the performance of 4-bit all-optical NOR gates based on fully integrable components for high speed all-optical look up tables. Feasibility of the proposed architecture is demonstrated by proof-of-concept experiments using both commercially available devices and photonic integrated circuits. [ABSTRACT FROM PUBLISHER]

We have investigated experimentally the pulse train (mode beating) stability of a monolithic mode-locked multi-section quantum-dot laser with an added passive auxiliary optical fiber cavity. Addition of the weakly coupled (≈ -24 dB) cavity reduces the current-induced shift dν / dΙ of the principal peak in the RF spectrum (the effective pulse repetition frequency) by more than an order of magnitude, from -39.5 to -2.3 kHz/mA. The rms timing jitter of the pulse train is simultaneously reduced from 1.4 to 0.9 ps. [ABSTRACT FROM AUTHOR]

In this letter, we present a new all-optical method for the measurement of the wavelength-resolved state-of-polarization vector across the bandwidth of multiple in-service channels. Taking advantage of the narrow spectral selectivity of stimulated Brillouin scattering and its dependence with the relative polarization alignment between the pump and the stimulus, polarization selective spectral measurements are performed on the signal under test. Obtaining the spectra for three pairs of orthogonal polarization states of the pump, the three Stokes parameters are retrieved for each spectral component. Differential group delay is then calculated from the spectral evolution of the polarization state. [ABSTRACT FROM PUBLISHER]

We report on results from the characterization of Stimulated Brillouin Scattering (SBS) spectra for standard single-mode fiber produced by the interaction between two counter-propagating tunable laser sources (TLS) using one as the probe signal to measure and the other as the pump, sweeping a wide span around the signal. Assuming TLS linewidth negligible against SBS gain bandwidth, we measure SBS spectrum for a wide range of pump and probe signal power levels and study the evolution of relevant SBS parameters such as linewidth and gain profile. High signal to noise ratio measurements allows analyzing the evolution of the SBS gain profile from Lorentzian to Gaussian as predicted by current theory of SBS and the use of SBS response for filtering applications.