Time domain add-drop multiplexing scheme enhanced using a saw-tooth pulse shaper

We experimentally demonstrate the use of saw-tooth optical pulses, which are shaped using a fiber Bragg grating, to achieve robust and high performance time-domain add-drop multiplexing in a scheme based on cross-phase (XPM) modulation in an optical fiber, with subsequent offset filtering. As compared to the use of more conventional pulse shapes, such as Gaussian pulses of a similar pulse width, the purpose-shaped saw-tooth pulses allow higher extinction ratios for the add and drop windows and significant improvements in the receiver sensitivity for the dropped and added channels

All-optical pulse reshaping and retiming systems incorporating pulse shaping fiber Bragg grating

This paper demonstrates two optical pulse retiming and reshaping systems incorporating superstructured fiber Bragg gratings (SSFBGs) as pulse shaping elements. A rectangular switching window is implemented to avoid conversion of the timing jitter on the original data pulses into pulse amplitude noise at the output of a nonlinear optical switch. In a first configuration, the rectangular pulse generator is used at the (low power) data input to a nonlinear optical loop mirror (NOLM) to perform retiming of an incident noisy data signal using a clean local clock signal to control the switch. In a second configuration, the authors further amplify the data signal and use it to switch a (low power) clean local clock signal. The S-shaped nonlinear characteristic of the NOLM results in this instance in a reduction of both timing and amplitude jitter on the data signal. The underlying technologies required for the implementation of this technique are such that an upgrade of the scheme for the regeneration of ultrahigh bit rate signals at data rates in excess of 320 Gb/s should be achievable

Novel Fiber Design for Wideband Conversion and Amplification in Multimode Fibers

We propose an operating principle to achieve broadband and highly tunable mode conversion and amplification exploiting inter-modal four wave mixing in a multimode fiber. A bandwidth of 30 nanometers is demonstrated by properly designing a simple step-index silica fiber.Comment: Ecoc conference 201

Quadrature decomposition of optical fields using two orthogonal phase sensitive amplifiers

We propose a new technique to optically process coherent signals by simultaneously extracting their two (I and Q) quadrature components into two orthogonal polarizations at the same frequency. Two possible implementations are demonstrated

Robust low loss splicing of hollow core photonic bandgap fiber to itself

Robust, low loss (0.16dB) splicing of hollow core photonic band gap fiber to itself is presented. Modal content is negligibly affected by splicing, enabling penalty-free 40Gbit/s data transmission over > 200m of spliced PBGF

Phase sensitive amplifiers for regeneration of phase encoded optical signal formats

We discuss the application of phase sensitive fiber optical parametric devices for the regenerative processing of high baud rate optical signals. We present recent advances in phase-sensitive amplification technology and its application to the regeneration of phase-encoded signals. By combining four wave mixing based parametric effects in highly nonlinear optical fibers and injection locking assisted synchronisation of multiple coherent lasers, we demonstrate how it possible to derive phase regeneration in signals with more than two levels of phase encoding

Efficient binary phase quantizer based on phase sensitive four wave mixing

We experimentally demonstrate an efficient binary phase quantizer operating at low pump powers. Phase-sensitive operation is obtained by polarization mixing the phase-locked signal/idler pair in a degenerate dual-pump vector parametric amplifier

Novel polarization-assisted phase sensitive optical signal processor requiring low nonlinear phase shifts

We demonstrate a new scheme to achieve binary step-like phase response and high phase-sensitive extinction ratio at low powers. Phase-sensitive operation is achieved by polarization filtering phase-locked signal/idler in a degenerate dual-pump vector parametric amplifier

Can firms be both broad and deep? Exploring interdependencies between horizontal and vertical firm scope

Firms can be horizontally diversified, with considerable breadth, or vertically integrated, with great depth. This study explores how breadth and depth affect each other as influenced by capability requirements and coordination demands. Using construction industry data, we assess the interdependence between contractors’ portfolios of building types (horizontal scope) and the extent of integration of the activities needed to complete each project (vertical scope). We find that vertical and horizontal scope have a negative interdependency only when contractors face managerial constraints due to coordination challenges. Further, we show that this effect can be mitigated through organizational structures that centralize key functions. Our findings highlight the importance of coordination in the theory of the firm, as we link firm boundaries to managerial coordination and internal organization