300 GHz wave generation based on a Kerr microresonator frequency comb stabilized to a low noise microwave reference.

In this Letter, we experimentally demonstrate low noise 300 GHz wave generation based on a Kerr microresonator frequency comb operating in the soliton regime. The spectral purity of a 10 GHz GPS-disciplined dielectric resonant oscillator is transferred to the 300 GHz repetition rate frequency of the soliton comb through an optoelectronic phase-locked loop. Two adjacent comb lines beat on a uni-traveling carrier photodiode emitting the 300 GHz millimeter-wave signal into a waveguide.

Continuous scanning of a dissipative Kerr-microresonator soliton comb for broadband, high-resolution spectroscopy.

Dissipative Kerr-microresonator soliton combs (hereafter called soliton combs) are promising to realize chip-scale integration of full soliton comb systems providing high precision, broad spectral coverage, and a coherent link to the micro/mm/THz domain with diverse applications coming on line all the time. However, the large soliton comb spacing hampers some applications. For example, for spectroscopic applications, there are simply not enough comb lines available to sufficiently cover almost any relevant absorption features.

All-optical tunable buffering with coupled ultra-high Q whispering gallery mode microcavities.

All-optical tunable buffering was recently achieved on a chip by using dynamically tuned coupled mode induced transparency, which is an optical analogue of electromagnetically induced transparency. However, the small Q s of about 10 used in those systems were limiting the maximum buffering time to a few hundred ps. Although employing an ultra-high Q whispering gallery mode (WGM) microcavity can significantly improve the maximum buffering time, the dynamic tuning of the WGM has remained challenging because thermo-optic and pressure tunings, which are widely used for WGM microcavities, have a very slow response.

Ultrasmall in-plane photonic crystal demultiplexers fabricated with photolithography.

We demonstrate ultrasmall demultiplexers based on photolithographic photonic crystals. The footprint of the demultiplexers is 110 μm per channel. Our in-plane demultiplexers are clad with silica, which makes them stable and easy to integrate with other silicon photonic devices.

Kerr-induced controllable adiabatic frequency conversion in an ultrahigh Q silica toroid microcavity.

In this Letter, we report, based on our knowledge, the first demonstration of Kerr-induced adiabatic frequency conversion in a silica toroid microcavity. Taking advantage of the instantaneous response of the Kerr effect, we achieved adiabatic frequency conversion with a controllable amount of frequency shift and time width. In addition, thanks to the combination of the Kerr effect and the ultrahigh Q (>10) of the silica toroid microcavity, we also observed multiple frequency conversion within a photon lifetime.

Compact resonant electro-optic modulator using randomness of a photonic crystal waveguide.

We fabricate and demonstrate an electro-optic modulator that utilizes the randomness in a photonic crystal waveguide. We exploit a way of using random photonic crystals for device application that involves restricting the area influenced by the randomness. Our random photonic crystal waveguide is in a diffusive regime and the confinement of light is observed only for a W0.

Observation of energy oscillation between strongly-coupled counter-propagating ultra-high Q whispering gallery modes.

We report the first experimental observation of an energy oscillation between two coupled ultra-high Q whispering gallery modes in the time domain. Two counter-propagating whispering gallery modes in a silica toroid microcavity were employed for this purpose. The combination of a large coupling coefficient between the two modes and an ultra-high Q factor, which creates a large Γ value of > 10, results in a clear energy oscillation.

High-Q coupled resonances on a PhC waveguide using a tapered nanofiber with high coupling efficiency.

We experimentally demonstrate high-Q cavity formation at an arbitrary position on a silicon photonic crystal waveguide by bringing a tapered nanofiber into contact with the surface of the slab. An ultrahigh Q of 5.1 × 10(5) is obtained with a coupling efficiency of 39%, whose resonant wavelength can be finely tuned by 27 pm by adjusting the contact length of the nanofiber.

CMOS compatible high-Q photonic crystal nanocavity fabricated with photolithography on silicon photonic platform.

Progress on the fabrication of ultrahigh-Q photonic-crystal nanocavities (PhC-NCs) has revealed the prospect for new applications including silicon Raman lasers that require a strong confinement of light. Among various PhC-NCs, the highest Q has been recorded with silicon. On the other hand, microcavity is one of the basic building blocks in silicon photonics.