Although Microcavities are promising in a variety of novel devices, there is slow development in microcavity based practical devices due to the lack of the package technology. In this paper, for the first time, we demonstrate the package technology for the microcavity coupling system to promote the development of the microcavity based practical applications. The package process are illustrated in detail. The changes which result from the package are also discussed. In addition, the advantages of the packaged structure are characterized, including the Q maintenance, robustness and the convenience. These advantages make this packaged structure promising in microcavity based practical devices.
The target of this paper is to design a novel water-vapor sensor used in humidity transducer system based on high-quality
factor (Q) spherical microcavities, which at present obtained the highest Q value induced by surface tension. Sensitive
mechanics and its high sensitivity are discussed according to optical loss sensitization to coupling system composed of a
microsphere cavity and a tapered fiber. After that, fabrication methods of master parts of the sensor in our lab are
introduced. Additionally, a sensing structure composed of a gas-chamber and a vacuum-chamber is also designed.
According to water absorption band, telecom band around 1550nm is used to pump the microsphere optical mode. In a
vacuum environment, a transmitted spectrum is obtained through output end, revealing some information about the core
system including the size of the microcavity and the optical loss of the regime. However, when the core system is placed
in a water vapor environment, the transmitted spectrum will change due to extra optical loss induced by water molecules
absorption, behaving as spectral shift, free spectrum range (FSR) or line width broadening. Contrasting and analyzing
two different spectrums in the two situations, the gas concentration can be deduced. Indispensable experiments were also
carried out, showing that, the two spectrums are different from resonance hump, formant strength and formant line
width. Even an ultra low water vapor concentration induced a measurable output signal, ensuring a high detecting
sensitivity. Certainly, the analyted vapor should not only be water vapor. This kind of sensitive mechanics is versatile.
Changing the pumping light corresponding to the analyted absorption band, we are able to detect a series of vapor.
Planar Microtoroid cavities with ultrahigh quality factor have very strong confined function to the electromagnetic wave
coupled into them due to their novel ring-like structures. Therefore, they have very good applications in high sensitivity
sensors and other micro optics components. In this paper, the Planar Microtoroid cavity and its coupling system
constructed together with the tapered fiber are introduced. Then, micro sensors based on the above coupling system are
designed. These sensors measure environmental parameters by means of monitoring the changes in the transmission
spectrum of the high finesse Planar Microtoroid cavities, obtaining fine resolution and high accuracy due to their
ultrahigh quality factor (Q) performance. The sensitive mechanism and the feasibility are demonstrated through optical
and mechanical software simulation. With software BeamPROP, the evident resonance and strengthened phenomenon to
the electromagnetic wave coupled into the micro-cavity are shown, which have a big relation with the light frequency.
The results indicate that, Planar Microtoroid cavity is very promising in designing new micro sensors.