Eun-Hwa Lee

Towards Multimodal Affective Feedback: Interaction between Visual and Haptic Modalities

We explored how emotional cues presented in visual and haptic modalities interact. We constructed an affective haptic dataset, and used the emotional visual stimuli from the International Affective Picture System (IAPS). Participants were asked to rate the visual stimuli, haptic stimuli and visualhaptic stimuli. Analysis of the results indicates that the presence of haptic stimulus affects the arousal of the visual stimulus, but does not affect the valence significantly. We further explored this interaction in terms of the intensity, frequency, waveform and rhythm of the haptic stimuli. We then provide a set of guidelines on visual-haptic interaction that could be used in design of multimodal affective feedback.

A single transverse mode operation of top surface emitting laser diode with a integrated photo-diode

In summary, we have fabricated a vertical cavity surface emitting laser (VCSEL) with an integrated photodiode. The device shows a stable fundamental operation throughout the entire range. The photodiode shows a linear responsivity to the laser output power up to the maximum power. The problem associated with spontaneous emission will be corrected by modifying the structure to prevent the absorption of extra spontaneous emission.

Characterization of the electro-absorption modulator chirp using modulated-transmission spectroscopy

The electroabsorption modulator still shows large transient chirp and thus is hard to operate at higher bit rate without a high insertion loss. To overcome this obstacle, it is imperative to fully understand the chirp characteristics caused by Stark effect in the multiple quantum-well (MQW) structures. This work presents a simple experimental method of measuring MQW electro-absorption and the chirp parameter.

High-power wide temperature range (-40°C ~100°C) operation of 1300-nm InGaAsP DFB lasers with asymmetric MQWs

We demonstrate 1.25 Gbps 1300 nm InGaAsP/InP DFB lasers employing asymmetric MQWs structures operable over a wide temperature range of -40°C to 100°C, which has an optical power of 10 mW and a side mode suppression ratio (SMSR)and a Fabry-Perot suppression ratio (FPSR) of >30dB.

InGaAsP SSC LD for low cost uncooled FTTH module with bandwidth over 4GHz

By optimum design of spot-size converter regarding the cavity length, active volume and taper type, we achieved SSC LD with 13degtimes14deg FFP, 3.5 dB coupling loss and 3 dB bandwidth over 4 GHz applicable to uncooled E-PON FTTH modules

Reliable and damage-free dry grating etching for the InGaAsP DFB laser diodes

We developed dry etching for the fabrication of DFB lasers. Most of all, effects of dry etching conditions such as rf power and etch mask materials on the etching properties and overgrown active layers were investigated. Device characteristics and long-term stability of DFB laser fabricated by using a dry etched grating were also measured.

High-density integrated VCSEL and PD arrays

We developed high performance VCSEL/photodiode arrays. These arrays show the ideal characteristics for high density applications where the uniform distributions of the power of single transverse mode of VCSEL and the sensitivities of PD are required.