Joo Beom Eom

Overcoupled bending insensitive holey optical fiber coupler

A holey optical fiber (HOF) wavelength division multiplexing (WDM) coupler, which divides optical waves according to their wavelengths, has been made by using the Fused Biconical Tapered (FBT) method. The transmission band of the proposing HOF WDM coupler could be easily tuned by adjusting the pulling length during the FBT process. The HOF used for the WDM coupler was designed to be bending insensitive, which could withstand a bending radius of up to 6 mm. Interestingly, it was observed that the air hole structure of the HOF should be maintained to have the property of a WDM coupler. The cross sectional SEM images of the implemented HOF WDM coupler are presented along with the light intensity distribution at the coupling region. The proposed HOF couplers may find applications as optical CWDM (coarse wavelength division multiplexing) filters and as optical fiber sensors also.

Thermal stability improvement of the optical probe which uses LEDs as an optical source

We improved thermal stability of an optical probe for near-infrared (NIR) fluorescence signal detection with a new liquid circulation module. From a measurement of temperature variation of the optical probe, we could confirm that the optical probe has thermal stability with a standard deviation of 2.19 °C under room temperature condition. We expect that an optical noise and signal decrease which can bring on by thermal problem in the optical probe decreased effectively in the optical probe.