Dan M. Marom

Soliton shedding from Airy pulses in Kerr media

We simulate and analyze the propagation of truncated temporal Airy pulses in a single mode fiber in the presence of self-phase modulation and anomalous dispersion as a function of the launched Airy power and truncation coefficient. Soliton pulse shedding is observed, where the emergent soliton parameters depend on the launched Airy pulse characteristics. The Soliton temporal position shifts to earlier times with higher launched powers due to an earlier shedding event and with greater energy in the Airy tail due to collisions with the accelerating lobes. In spite of the Airy energy loss to the shed Soliton, the Airy pulse continues to exhibit the unique property of acceleration in time and the main lobe recovers from the energy loss (healing property of Airy waveforms).

Spatial Superchannel Routing in a Two-Span ROADM System for Space Division Multiplexing

We report a two-span, 67-km space-division-multiplexed (SDM) wavelength-division-multiplexed (WDM) system incorporating the first reconfigurable optical add-drop multiplexer (ROADM) supporting spatial superchannels and the first cladding-pumped multicore erbium-doped fiber amplifier directly spliced to multicore transmission fiber. The ROADM subsystem utilizes two conventional 1 × 20 wavelength selective switches (WSS) each configured to implement a 7 × (1 × 2) WSS. ROADM performance tests indicate that the subchannel insertion losses, attenuation accuracies, and passband widths are well matched to each other and show no significant penalty, compared to the conventional operating mode for the WSS. For 6 × 40 × 128-Gb/s SDM-WDM polarization-multiplexed quadrature phase-shift-keyed (PM-QPSK) transmission on 50 GHz spacing, optical signal-to-noise ratio penalties are less than 1.6 dB in Add, Drop, and Express paths. In addition, we demonstrate the feasibility of utilizing joint signal processing of subchannels in this two-span, ROADM system.

Switching solutions for WDM-SDM optical networks

Over the last few decades, network traffic has consistently grown at an exponential rate and was efficiently satisfied using WDM and more efficient coding schemes requiring coherent detection. There is no indication that the network traffic growth trend will cease anytime soon, and we are nearing the day when the capacity of the ubiquitous single-mode fiber will be fully exploited. Space-domain multiplexing (SDM) for high-capacity transmission is the promising solution with the scaling potential to meet future capacity demands. However, there is still a large technological gap between current WDM optical communication system designs and SDM network implementations. In this article we lay the foundation of switching node designs for future WDM-SDM optical networks.

MEMS-based channelized dispersion compensator with flat passbands

This paper describes a continuously variable and independently addressable channelized dispersion compensator. The optical system is a free-space grating-based system used in a four-pass configuration to ensure flat passbands. The variable dispersion is produced by an array of thermally adaptable curvature micromechanical mirrors. A per-channel variable dispersion greater than +/-400 ps/nm has been demonstrated, with 58 GHz +/-0.4 dB flat passband on 85 GHz spacing. The group delay ripple is less than 7 ps and the penalty with 40 Gb/s CSRZ is 0.7 dB.

Sub-banded / single-sub-carrier drop-demux and flexible spectral shaping with a fine resolution photonic processor

Spectral processor based on arrayed waveguide grating and free-space manipulation is capable of arbitrary filtering at record metrics of 0.8GHz resolution over 200GHz span. Narrowband coherent drop-demultiplexing and controlled optical shaping is demonstrated in unison with digital sub-banding.

Airy-soliton interactions in Kerr media.

We investigate and analyze temporal soliton interactions with a dispersive truncated Airy pulse traveling in a nonlinear fiber at the same center wavelength (or frequency), via split step Fourier numerical simulation. Truncated Airy pulses, which remain self-similar during propagation and have a ballistic trajectory in the retarded time frame, can interact with a nearby soliton by its accelerating wavefront property. We find by tracking the fundamental parameters of the emergent soliton-time position, amplitude, phase and frequency-that they alter due to the primary collision with the Airy main lobe and the continuous co-propagation with the dispersed Airy background. These interactions are found to resemble coherent interactions when the initial time separation is small and incoherent at others. This is due to spectral content repositioning within the Airy pulse, changing the nature of interaction from coherent to incoherent. Following the collision, the soliton intensity oscillates as it relaxes. The initial parameters of the Airy pulse such as initial phase, amplitude and time position are varied to better understand the nature of the interactions.

Gender Dynamics in Crowdfunding (Kickstarter): Evidence on Entrepreneurs, Investors, Deals and Taste-Based Discrimination

In this paper we investigate whether a new form of venture financing – crowdfunding – reduces the barriers of female entrepreneurs to raise capital. Specifically, we investigate gender dynamics and biases in the process of raising funding to new projects via the leading crowdfunding platform – Kickstarter. We find women made up about 35% of the project leaders and 44% of the investors on the platform. On average, men seek significantly higher levels of capital than women for their projects, and also raise more funds than women. However, women enjoy higher rates of success in funding their projects, even after controlling for category and goal amount. Only about 23% of projects that men invested in had female project leads. Conversely, more than 40% of projects that women invested in had female project leads. Multivariate analysis indicated significant positive correlation between the gender of the project leader and the percentage of the same gender investors. Questions arise around what factors explain the fact that female-led projects are predominantly financed by women. In an attempt to disentangle taste-based discrimination from statistical discrimination we conducted a survey of investors from the Kickstarter platform and find evidence that some of lower investment in female-led projects by men can be attributed to taste-based discrimination.

A photonic spectral processor employing two-dimensional WDM channel separation and a phase LCoS modulator

We propose and demonstrate a spectral phase and amplitude modulator spanning full 2D-space by crossing a 100 GHz WGR and a 1200 gr/mm bulk grating. We address individual WDM channels with high resolution (4.5 GHz) and addressability (0.2 GHz).

Hybrid Guided-Wave/Free-Space Optics Photonic Spectral Processor Based on LCoS Phase Only Modulator

We propose and demonstrate a photonic spectral processor for applying arbitrary spectral phase and amplitude at high resolution with a 100-GHz free-spectral range for colorless wavelength-division-multiplexing adaptive filtering applications. The system employs free-space optics for projecting the dispersed light coming out of a planar-lightwave circuit onto a phase spatial-light modulator. The processor achieves 3-GHz optical resolution over 75-GHz usable bandwidth, with 557-MHz addressable granularity.

OFDM/WDM PON with laserless, colorless 1 Gb/s ONUs based on Si-PIC and slow IC

We introduce a next-generation long-reach access optical network (35 dB loss budget +2 dB margin) delivering up to 40G/40G per passive 1:256 optical distribution network, supporting symmetrical 1 Gb/s rates per home user or up to 40 Gb/s for business users (e.g., enterprises, antenna sites). The proposed system is based on a novel spectrally efficient orthogonal frequency division multiplexing/wavelength division multiplexing OFDM/WDM architecture symmetrically using 16-QAM OFDM polarization diversity in both the downstream and upstream in order to serve low-cost energy-efficient symmetric 1 Gb/s optical network units (ONUs), which are self-coherent, laserless, colorless, and tunable-filter-free. Each ONU comprises a standard semiconductor optical amplifier (SOA), a silicon-based photonic integrated circuit (PIC), and mixed-signal electronic integrated circuits (ICs) performing the signal processing at a relatively slow rate as compared with the overall passive optical network (PON) throughput: digital to analog converters (DACs) and analog to digital converters (ADCs) at 417 MS/s for the home user ONUs.