다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

In order to enable optical systems to operate with a high degree of compactness and reliability it is necessary to combine large number of optical functions in small monolithic structures. A development, somewhat reminiscent of that that took place in Integrated Electronics, is now beginning to take place in optics. The initial challenge in this emerging field, known appropriately as "Integrated Optics", is to demonstrate the possibility of performing basic optical functions such as light generation, coupling, modulation, and guiding in Integrated Optical configurations. The talk will review the main theoretical and experimental developments to date in Integrated Optics. Specific topics to be discussed include: Material considerations, guiding mechanisms, modulation, coupling and mode losses. The fabrication and applications of periodic thin film structures will be discussed.

Integrated optics

Natural ventilation of buildings is the flow generated by temperature differences and by the wind. The governing feature of this flow is the exchange between an interior space and the external ambient. Although the wind may often appear to be the dominant driving mechanism, in many circumstances temperature variations play a controlling feature on the ventilation since the directional buoyancy force has a large influence on the flow patterns within the space and on the nature of the exchange with the outside. Two forms of ventilation are discussed: mixing ventilation, in which the interior is at an approximately uniform temperature, and displacement ventilation, where there is strong internal stratification. The dynamics of these buoyancy-driven flows are considered, and the effects of wind on them are examined. The aim behind this work is to give designers rules and intuition on how air moves within a building; the research reveals a fascinating branch of fluid mechanics.

The fluid mechanics of natural ventilation

Mode-division multiplexing technology using the high-order modes of multimode waveguides enables high-bandwidth data transmission. High-speed mode channel switching is a pivotal function for these optical networks. Here, we propose a modal switching scheme on a silicon-on-insulator platform and demonstrate a high-speed two-mode switch that exploits a Y-junction and multimode interference structure. The design allows for simultaneous switching of two optical modes. A PN-doped junction-based phase shifter in one branch of a Y-junction enables dynamic switching in 2.5 ns. The measured switching extinction ratio is 12.5 dB or better with an open eye diagram for a 10 Gb/s on–off key optical payload signal. The optical power penalty is within 0.5 dB for the two-mode switching at a bit error rate of 10−9. This two-mode switch could enable on-chip mode-based switching network topology for greater aggregated throughput capacity.

High-speed two-mode switch for mode-division multiplexing optical networks

The remarkable achievements in the area of integrated optical memories and optical random access memories (RAMs) together with the rapid adoption of optical interconnects in the Datacom and Computercom industries introduce a new perspective for information storage directly in the optical domain, enabling fast access times, increased bandwidth and transparent cooperation with optical interconnect lines. This article reviews state-of-the-art integrated optical memory technologies and optical RAM cell demonstrations describing the physical mechanisms of several key devices along with their performance metrics in terms of their energy, speed and footprint. Novel applications are outlined, concluding with the scaling challenges to be addressed toward allowing light to serve as both a data-carrying and data-storage medium.

/pdf/optical-ram-and-integrated-optical-memories-a-survey-1ck0pup5o8.pdf

Optical RAM and integrated optical memories: a survey

For realizing compact breath sensing device, we have proposed a silica high-mesa waveguide for the gas-cell (breath detection part) because of its low propagation loss. It is, however, still difficult to make breath-sensing due to its total insertion loss because the required length of the waveguide reaches very long of approximately several 10 cm–1m for the small portion of gas, and thus gas-sensing has not been achieved so far. To compensate the insertion loss, we utilize “amplified” CRDS (cavity ring down spectroscopy) technique to realize gas-sensing in this paper. As a result, we could successfully confirm the gas-sensing of CO2 with using the waveguide gas-cell for the first time.

Gas sensing demonstration by using silica high-mesa waveguide with amplified cavity ring down spectroscopy technique

https://iopscience.iop.org/article/10.7567/1347-4065/ab1e3d/pdf

Amplifier-assisted CRDS (cavity ring-down spectroscopy) toward compact breath sensing

We demonstrate fast and low energy all optical flip-flop devices based on asymmetric active-multimode interferometer using high-mesa waveguide structure. The implemented devices showed high speed all-optical flip-flop operation with 25ps long pulses. The rising and falling times of the output signal were 121 ps and 25 ps, respectively. The required set and reset pulse energies were only 7.1 fJ and 3.4 fJ, respectively.

/pdf/all-optical-flip-flop-operation-based-on-asymmetric-active-2yqg9wt6bl.pdf

All-optical flip-flop operation based on asymmetric active-multimode interferometer bi-stable laser diodes.

Multi-mode interference (MMI) couplers (waveguides) are widely studied and developed as key components of photonic integrated circuits, including power coupler/dividers, and others. Furthermore, another possibility utilizing MMI has been investigated on active devices so far. Owing to the wider area of the multi-mode waveguide section compared with that of the regular single-mode waveguide, MMI may result in higher performance (high power, low power consumption, and others) rather than conventional active devices while maintaining regular single-mode output. Thus, active multi-mode interferometer (active-MMI) devices, including laser diodes (LDs), super-luminescent light emitting diodes (SLEDs), and semiconductor optical amplifiers (SOAs) have been studied. Moreover, they have been also exploited to bi-stable LDs and single wavelength emitters, and others using the interference inside the MMI section. In this paper, we review and summarize the recent progress in active MMI devices. We provide proof of MMI phenomena in active waveguides and discuss the results.

https://iopscience.iop.org/article/10.1088/0022-3727/48/38/383001/pdf

Haisong Jiang

Papers

Gas sensing demonstration by using silica high-mesa waveguide with amplified cavity ring down spectroscopy technique

Amplifier-assisted CRDS (cavity ring-down spectroscopy) toward compact breath sensing

All-optical flip-flop operation based on asymmetric active-multimode interferometer bi-stable laser diodes.

Active MMI devices: concept, proof, and recent progress

CW single-wavelength emission by using novel asymmetric configuration for active multi-mode interferometer laser diodes