Channel cloning by multi-mode phase-sensitive parametric mixer.

We investigate high fidelity channel replication approaching the idealized notion of channel cloning with negligible excess noise and distortion. Previously proposed cloning architectures require that the channel carriers to be externally seeded, limiting their ultimate usefulness, whereas the self-seeded approach limits the channel number and signal-to-noise ratio. Specifically, when a single channel is replicated, the noise figure (NF) remains above the well-known 3-dB limit, and multi-channel replication by a dual-pump driven parametric mixer faces a theoretical NF limit of 6-dB.

Ultra-broadband multimode 3dB optical power splitter using an adiabatic coupler and a Y-branch.

As an essential component of mode division multiplexing (MDM) system, a multimode 3dB power splitter with low loss, high power balance, and low mode crosstalk is highly desired. In this paper, we propose an ultra-broadband on-chip multimode 3dB optical power splitter using an adiabatic coupler and an S-bend based Y-branch. As an example, a splitter for the four-lowest modes of a rib waveguide on silicon on insulator (SOI) platform is designed.

Octave-spanning coherent supercontinuum generation in silicon on insulator from 1.06 μm to beyond 2.4 μm.

Efficient complementary metal-oxide semiconductor-based nonlinear optical devices in the near-infrared are in strong demand. Due to two-photon absorption in silicon, however, much nonlinear research is shifting towards unconventional photonics platforms. In this work, we demonstrate the generation of an octave-spanning coherent supercontinuum in a silicon waveguide covering the spectral region from the near- to shortwave-infrared.

In Vivo Sarcomere Length Measurement in Whole Muscles during Passive Stretch and Twitch Contractions.

Muscle force is dictated by micrometer-scale contractile machines called sarcomeres. Whole-muscle force drops from peak force production to zero with just a few micrometers of sarcomere length change. No current technology is able to capture adequate dynamic sarcomere data in vivo, and thus we lack fundamental data needed to understand human movement and movement disorders.

All optical wavelength multicaster and regenerator based on four-mode phase-sensitive parametric mixer.

Four-mode phase-sensitive (4MPS) process has been employed in a parametric mixer based wavelength multicaster, enhancing the multicasting conversion efficiency and signal-to-noise ratio. In addition, the 4MPS parametric multicaster is an outstanding candidate for all-optical regeneration, owing to its inherent capabilities to clamp amplitude fluctuations by the saturated parametric effect and to squeeze phase distortions by the phase sensitive process. The investigation in this paper focuses on the 4MPS multicaster operated in the saturation gain regime, including theoretical simulations and experimental demonstrations on amplitude and phase noise regeneration over 20 multicasting signal copies.

Digital multi-channel stabilization of four-mode phase-sensitive parametric multicasting.

Stable four-mode phase-sensitive (4MPS) process was investigated as a means to enhance two-pump driven parametric multicasting conversion efficiency (CE) and signal to noise ratio (SNR). Instability of multi-beam, phase sensitive (PS) device that inherently behaves as an interferometer, with output subject to ambient induced fluctuations, was addressed theoretically and experimentally. A new stabilization technique that controls phases of three input waves of the 4MPS multicaster and maximizes CE was developed and described.

Low-noise parametric frequency comb for continuous C-plus-L-band 16-QAM channels generation.

A low phase noise frequency comb generated from a continuous-wave seed is experimentally demonstrated across continuous C- and L-bands. Parametrically generated carriers with optical signal-to-noise ratio in excess of 45 dB were used to generate 16-ary quadrature amplitude modulated signals. We characterize 20 GBaud channels' performance that was varied by only 1.

Noise performance of phase-insensitive frequency multicasting in parametric mixer with finite dispersion.

Noise performance of dual-pump, multi-sideband parametric mixer operated in phase-insensitive mode is investigated theoretically and experimentally. It is shown that, in case when a large number of multicasting idlers are generated, the noise performance is strictly dictated by the dispersion characteristics of the mixer. We find that the sideband noise performance is significantly degraded in anomalous dispersion region permitting nonlinear noise amplification.

Phase-preserving parametric wavelength conversion to SWIR band in highly nonlinear dispersion stabilized fiber.

The first successful translation of a phase modulated optical signal over 80 THz, from the near infrared to the short-wave infrared (SWIR) band is demonstrated. A signal, phase-modulated at 10 Gbps, was received in an error-free manner in the SWIR(1.7-2.

Photonic preprocessor for analog-to-digital-converter using a cavity-less pulse source.

A photonic preprocessor for analog to digital conversion is demonstrated and characterized using a cavity-less optical pulse source. The pulse source generates high fidelity pulses at 2 GHz repetition rate with temporal width of 3 ps. Chirped pulses are formed by cascaded amplitude and phase modulators, and subsequently compressed in dispersion compensating fiber.

Broadband parametric multicasting via four-mode phase-sensitive interaction.

Optical frequency multicasting with significantly enhanced signal-to-noise-ratio (SNR) is demonstrated over wide wavelength range. High-fidelity multicasting relies on a four-mode phase-sensitive (PS) parametric process. Four-mode seeding was used to drive dual-pump, multistage mixer and achieve high-efficiency frequency comb generation and signal replication assisted by field interference.

Dispersion-stabilized highly-nonlinear fiber for wideband parametric mixer synthesis.

Conventional highly-nonlinear fiber (HNLF) designs are optimized for high field-confinement but are also inherently susceptible to dispersion fluctuations. The design compromise prevents fiber-optical parametric mixers from possessing high power efficiency and extended operating bandwidth simultaneously. Using a new fiber waveguide design, we have fabricated and tested a new class of HNLF that possesses a significantly lower level of dispersion fluctuations while maintaining a high level of field-confinement comparable to that in conventional HNLFs.

Continuous-wave, short-wavelength infrared mixer using dispersion-stabilized highly-nonlinear fiber.

A new type of highly nonlinear fiber (HNLF) was designed and fabricated. The new HNLF was engineered to reduce dispersion shift due to transverse fluctuations while maintaining the modal confinement superior to that of the conventional fibers. The new design strategy was validated by the measurements of the global and local dispersive characteristics under considerable core and index profile deformation induced by tensile stress, which indicated that the dispersive and phase matching characteristics of the fiber did not change even under the highest tensile stress.

Spectral linewidth preservation in parametric frequency combs seeded by dual pumps.

We demonstrate new technique for generation of programmable-pitch, wideband frequency combs with low phase noise. The comb generation was achieved using cavity-less, multistage mixer driven by two tunable continuous-wave pump seeds. The approach relies on phase-correlated continuous-wave pumps in order to cancel spectral linewidth broadening inherent to parametric comb generation.

Highly nonlinear fiber with dispersive characteristic invariant to fabrication fluctuations.

New class of highly nonlinear fibers possessing dispersive characteristics invariant to transverse geometry fluctuations is described. The sensitivity to stochastic core fluctuations is reduced by order of magnitude while maintaining the fiber nonlinear coefficient. The effectiveness of the new highly nonlinear fiber type is demonstrated on stochastically perturbed distant-band mixer that could not be previously constructed with high-confinement fiber.

Generation of wideband frequency combs by continuous-wave seeding of multistage mixers with synthesized dispersion.

We numerically and experimentally demonstrate efficient generation of an equalized optical comb with 150-nm bandwidth. The comb was generated by low-power, continuous-wave seeds, eliminating the need for pulsed laser sources. The new architecture relies on efficient creation of higher-order mixing tones in phase-matched nonlinear fiber stages separated by a linear compressor.

Fast wideband source tuning by extra-cavity parametric process.

Fundamental and practical performance limits of continuously tunable optical sources using extra-cavity mixing process are examined. While the parametric process cannot overcome the fundamental tunable limit set by the uncertainty principle, it offers a new path in overcoming the practical performance limits associated with conventional tunable lasers. Specifically, cavity reconfiguration speed is recognized as a limiting process in all tunable lasers that cannot be circumvented by any conventional approach.

1.56-micros continuously tunable parametric delay line for a 40-Gb/s signal.

Experimental demonstration of an all-fiber, all-optical continuously tunable delay line is reported. The 1.56-micros delay with a record 62,400 time-delay bit-rate product was characterized for a 40-Gbps data channel.

Pulsed pump wavelength exchange for high speed signal de-multiplexing.

We report the first experimental demonstration of pulsed pump wavelength exchange in a highly nonlinear dispersion-shifted fiber for all-optical time de-multiplexing of 80 Gb/s return-to-zero (RZ) signals. Orthogonal pulsed pump and continuous wave (cw) pump are used in the fiber-based wavelength exchange for ultra-fast power switching. Error-free operation was achieved for the proposed all-optical 1:8 de-multiplexer over all time de-multiplexed 10 Gb/s RZ signals with View Article and Find Full Text PDF