Guided wave optics in periodically poled KTP: quadratic nonlinearity and prospects for attosecond jitter characterization

For the first time to our knowledge, continuous nonsegmented channel waveguides in periodically poled KTiOPO4 with guided orthogonal polarizations are used to demonstrate type II background-free second harmonic generation in the telecom band with 1.6%/(W cm2) normalized conversion efficiency. This constitutes a 90-fold improvement in aggregate conversion efficiency over its free space counterpart. Simulations show that the guided wave device should enable the measurement of timing fluctuations of optical pulse trains at the attosecond level in an optical cross correlation scheme

Ultrafast nonlinear optical processes and free-carrier lifetime in silicon nanowaveguides

Abstract: We report self-consistent femtosecond studies of two-photon absorption, optical Kerreffect and free-carrier index and loss in silicon nanowaveguides using heterodyne pump-probe. Free-carrier lifetime was reduced to 33ps with only 8dB/cm added loss using proton bombardment

1.2-km Timing-Stabilized, Polarization-Maintaining Fiber Link with Sub-Femtosecond Residual Timing Jitter

A 1.2-km timing-stabilized, polarization-maintaining fiber link based on balanced optical cross-correlationwas demonstrated with ~0.9 fs RMS timing jitter over 16 days and ~0.2 fs RMS timing jitter over 3 days

Efficient second harmonic generation in the optical telecom S-band using non-segmented PPKTP waveguides

Continuous channel waveguides in periodically poled KTiOPO[subscript 4] with guided orthogonal polarizations are used to demonstrate type-II background-free second harmonic generation at 1505 nm with 1.2 %/(W cm[superscript 2]) normalized efficiency

Integrated optical phase locked loop

Abstract: A silicon photonics based integrated optical phase locked loop is utilized to synchronize a 10.2 GHz voltage controlled oscillator with a 509 MHz mode locked laser, achieving 32 fs integrated jitter over 300 kHz bandwidth

Towards a Large-Scale, Optical Timing Distribution System with Sub-Femtosecond Residual Timing Jitter

We present here key developments for an all-optical timing distribution system with sub-femtosecond precision. Timing distribution over a 1.2-km polarization-maintaining, fiber-optic link using balanced optical cross-correlators (BOC) for link stabilization was demonstrated for 16 days with 0.6 fs RMS timing drift and during a 3-day interval only 0.13 fs drift. Jitter characterization of two identical commercial femtosecond lasers using the BOC method verified sub-100-as timing jitter for frequencies greater than 1 kHz. Preliminary operation of a fiber coupled, hybrid-integrated BOC using periodically-poled KTiOPO4 (PPKTP) waveguides indicate great potential for improved BOC timing sensitivities and overall system efficiency

Ultrafast nonlinear optical studies of silicon nanowaveguides

Results of a self-consistent ultrafast study of nonlinear optical properties of silicon nanowaveguides using heterodyne pump-probe technique are reported. The two-photon absorption coefficient and free-carrier absorption effective cross-section were determined to be 0.68cm/GW, and 1.9x10(-17) cm2, respectively and the Kerr coefficient and free-carrier-induced refractive index change 0.32x10(-13) cm2/W, and -5.5x10(-21) cm3, respectively. The effects of the proton bombardment on the linear loss and the carrier lifetime of the devices were also studied. Carrier lifetime reduction from 330ps to 33ps with a linear loss of only 14.8dB/cm was achieved using a proton bombardment level of 10(15)/cm2

Photonic ADC: overcoming the bottleneck of electronic jitter

Accurate conversion of wideband multi-GHz analog signals into the digital domain has long been a target of analog-to-digital converter (ADC) developers, driven by applications in radar systems, software radio, medical imaging, and communication systems. Aperture jitter has been a major bottleneck on the way towards higher speeds and better accuracy. Photonic ADCs, which perform sampling using ultra-stable optical pulse trains generated by mode-locked lasers, have been investigated for many years as a promising approach to overcome the jitter problem and bring ADC performance to new levels. This work demonstrates that the photonic approach can deliver on its promise by digitizing a 41 GHz signal with 7.0 effective bits using a photonic ADC built from discrete components. This accuracy corresponds to a timing jitter of 15 fs - a 4-5 times improvement over the performance of the best electronic ADCs which exist today. On the way towards an integrated photonic ADC, a silicon photonic chip with core photonic components was fabricated and used to digitize a 10 GHz signal with 3.5 effective bits. In these experiments, two wavelength channels were implemented, providing the overall sampling rate of 2.1 GSa/s. To show that photonic ADCs with larger channel counts are possible, a dual 20-channel silicon filter bank has been demonstrated