Nonlinear absorption and dispersion in fiber coupled silicon photonic crystal microresonators

Two-photon absorption, free-carrier absorption and dispersion, and thermo-optic dispersion in high-Q, ultra-small mode volume, photonic crystal cavities are studied experimentally. Sub-nanosecond free-carrier lifetimes, and optical bistability at ∼ 100μW cavity input power are observed

Fabrication-tolerant high quality factor photonic crystal microcavities

A two-dimensional photonic crystal microcavity design supporting a wavelength-scale volume resonant mode with a calculated quality factor (Q) insensitive to deviations in the cavity geometry at the level of Q~2x10^4 is presented. The robustness of the cavity design is confirmed by optical fiber-based measurements of passive cavities fabricated in silicon. For microcavities operating in the lambda = 1500 nm wavelength band, quality factors between 1.3-4.0x10^4 are measured for significant variations in cavity geometry and for resonant mode normalized frequencies shifted by as much as 10% of the nominal value.Comment: 3 pages, 3 figure

Evanescent coupling from optical fiber tapers to photonic crystal waveguides and resonators

Using a coupled mode theory and finite-difference time-domain calculations nearly complete evanescent power transfer between a fiber taper and a photonic crystal defect waveguide which is ideal for probing high-Q cavities is predicted

Design of high-Q photonic crystal optical cavities through Fourier space methods

By describing radiation losses through a Fourier space picture of modal couplings, low loss photonic crystal cavities are designed using a group theory-based analysis and finite difference time domain calculations, resulting in predicted quality factors exceeding 10^5

Efficient input and output coupling between planar photonic crystal waveguides and fiber tapers

Highly efficient (>94%) contradirectional coupling into and out of a photonic crystal waveguide is measured using a fiber taper probe as both a source and a collector

An optical fiber-based probe for photonic crystal microcavities

We review a novel method for characterizing both the spectral and spatial properties of resonant cavities within two-dimensional photonic crystals (PCs). An optical fiber taper serves as an external waveguide probe whose micron-scale field is used to source and couple light from the cavity modes, which appear as resonant features in the taper's wavelength-dependent transmission spectrum when it is placed within the cavity's near field. Studying the linewidth and depth of these resonances as a function of the taper's position with respect to the resonator produces quantitative measurements of the quality factor Q and modal volume Veff of the resonant cavity modes. Polarization information about the cavity modes can be obtained by studying their depths of coupling when the cavity is probed along different axes by the taper. This fiber-based technique has been used to measure Q ~ 40,000 and Veff ~ 0.9 cubic wavelengths in a graded square lattice PC microcavity fabricated in silicon. The speed and versatility of this fiber-based probe is highlighted, and a discussion of its applicability to other wavelength-scale resonant elements is given.Comment: Submitted to special section on photonic crystals from the PECS-V conference in IEEE Journal on Selected Areas in Communications (J-SAC), Nanotechnologies for Communications issu

Highly efficient coupling to photonic crystal waveguides from optical fiber tapers

Nearly-complete mode-selective coupling from an optical fiber taper to a photonic crystal defect waveguide is demonstrated experimentally. We observe 95% power transfer with a 20 nm bandwidth and a coupling length less then 65 µm

Probing the dispersive and spatial properties of planar photonic crystal waveguide modes via highly efficient coupling from optical fiber tapers

The demonstration of an optical fiber based probe for efficiently exciting the waveguide modes of high-index contrast planar photonic crystal (PC) slabs is presented. Utilizing the dispersion of the PC, fiber taper waveguides formed from standard silica single-mode optical fibers are used to evanescently couple light into the guided modes of a patterned silicon membrane. A coupling efficiency of approximately 95% is obtained between the fiber taper and a PC waveguide mode suitably designed for integration with a previously studied ultra-small mode volume high-Q PC resonant cavity [1]. The micron-scale lateral extent and dispersion of the fiber taper is also used as a near-field spatial and spectral probe to study the profile and dispersion of PC waveguide modes. The mode selectivity of this wafer-scale probing technique, together with its high efficiency, suggests that it will be useful in future quantum and non-linear optics experiments employing planar PCs