Jeremy Bolger

Dispersion Trimming in a Reconfigurable Wavelength Selective Switch

We experimentally demonstrate dispersion compensation in a wavelength selective switch, and characterize the bandwidth-dispersion product. At a channel bit-rate of 80 Gbit/s, we compensate for various amounts of dispersion (up to ±60 ps/nm), tunable for each wavelength division multiplexed channel, solely by adjusting the phase front of the optical signal inside the wavelength selective switch. Error-free operation is obtained for all of the channels, and for each output port after propagation over various lengths of dispersive fiber.

Microstructured optical fiber photonic wires with subwavelength core diameter

We demonstrate fabrication of robust, low-loss silica photonic wires using tapered microstructured silica optical fiber. The fiber is tapered by a factor of fifty while retaining the internal structure and leaving the air holes completely open. The air holes isolate the core mode from the surrounding environment, making it insensitive to surface contamination and contact leakage, suggesting applications as nanowires for photonic circuits . We describe a transition between two different operation regimes of our photonic wire from the embedded regime, where the mode is isolated from the environment, to the evanescent regime, where more than 70% of the mode intensity can propagate outside of the fiber. Interesting dispersion and nonlinear properties are identified.

Highly stable ultrabroadband mid-IR optical parametric chirped-pulse amplifier optimized for superfluorescence suppression.

We present a 9 GW peak power, three-cycle, 2.2 microm optical parametric chirped-pulse amplification source with 1.5% rms energy and 150 mrad carrier envelope phase fluctuations. These characteristics, in addition to excellent beam, wavefront, and pulse quality, make the source suitable for long-wavelength-driven high-harmonic generation. High stability is achieved by careful optimization of superfluorescence suppression, enabling energy scaling.

Compact tunable microfluidic interferometer

We demonstrate a compact tunable filter based on a novel microfluidic single beam Mach-Zehnder interferometer. The optical path difference occurs during propagation across a fluid-air interface (meniscus), the inherent mobility of which provides tunability. Optical losses are minimized by optimizing the meniscus shape through surface treatment. Optical spectra are compared to a 3D beam propagation method simulations and good agreement is found. Tunability, low insertion loss and strength of the resonance are well reproduced. The device performance displays a resonance depth of -28 dB and insertion loss maintained at -4 dB.

Nonlinear propagation effects in antiresonant high-index inclusion photonic crystal fibers.

We experimentally and numerically investigate femtosecond-pulse propagation in a microstructured optical fiber consisting of a silica core surrounded by airholes that are filled with a high-index fluid. This fiber combines the resonant properties of hollow-core bandgap fibers and the high nonlinearity of index-guiding waveguides. A range of nonlinear optical effects can be observed, including soliton propagation, dispersive wave generation, and a Raman self-frequency shift. Tuning the center wavelength of the laser and varying the refractive index of the fluid lead to different propagation effects, mediated by the strongly wavelength-dependent group-velocity dispersion in these photonic bandgap confining structures.

Nonlinear pulse propagation at zero dispersion wavelength in anti-resonant photonic crystal fibers

We experimentally and numerically investigate femtosecond pulse propagation in a microstructured optical fiber consisting of a silica core surrounded by air holes which are filled with a high index fluid. Such fibers have discrete transmission bands which exhibit strong dispersion arising from the scattering resonances of the high index cylinders. We focus on nonlinear propagation near the zero dispersion point of one of these transmission bands. As expected from theory, we observe propagation of a red-shifted soliton which radiates dispersive waves. Using frequency resolved optical gating, we measure the pulse evolution in the time and frequency domains as a function of both fiber length and input power. Experimental data are compared with numerical simulations.

Generation of a 4 /spl times/ 100 GHz pulse-train from a single-wavelength 10-GHz mode-locked laser using superimposed fiber Bragg gratings and nonlinear conversion

In this paper, the design of a simple and practical repetition-rate multiplier based on superimposed-chirped fiber Bragg gratings (FBGs) is presented. A tenfold increase in the repetition rate of a mode-locked fiber source, by generating a 100-GHz optical pulse train from a 10-GHz train, is demonstrated experimentally. As compared with previous demonstrations, the superimposed FBG filter was specifically designed to decrease the duty cycle of the generated pulse train or, in other words, decrease the pulsewidth. In addition, a fiber nonlinear optical loop mirror (NOLM) is used to eliminate the pulse-to-pulse phase fluctuations in the output high-repetition-rate train and to achieve a wavelength-tunable transform-limited pulse sequence. Moreover, it is shown that nonlinear conversion using the NOLM can be used to simultaneously generate multiwavelength high-repetition-rate optical pulse trains (4 /spl times/ 100 GHz in the example shown here).

Polychromatic nonlinear surface modes generated by supercontinuum light

We study propagation of polychromatic light near the edge of a nonlinear waveguide array. We describe simultaneous spatial and spectral beam reshaping associated with power and wavelength-dependent tunneling between the waveguides. We present experimental verifications of the effects predicted theoretically including the first observation of supercontinuum nonlinear surface modes.

All-optical self-switching in optimized phase-shifted fiber Bragg grating.

We experimentally demonstrate all-optical self-switching based on sub nanosecond pulse propagation through an optimized fiber Bragg grating with a pi phase-jump. The jump acts as a cavity leading to an intensity enhancement by factor 19. At pulse peak powers of 1.5 kW we observe 4.2 dB nonlinear change in transmission. Experimental results are consistent with numerical simulations.

Multi-wavelength synchronous pulse burst generation with a wavelength selective switch

We demonstrate simultaneous pulse-shaping at different ports of a rapidly tunable wavelength selective switch at a base rate of 40 GHz, based on Fourier-domain pulse shaping. Various pulse bursts are generated and accurately characterized with a linear spectrographic method.