Exquisite jade carving: figures, animals, ornaments

Exhibition held at the University Museum and Art Gallery, University of Hong Kong on Dec. 6, 1995-Feb. 6, 1996.published_or_final_versionFurther comments on flying deity/winged figure 17Foreword Lau, Michael W.M. Lau, Michael W.M. 4List of lenders 18借出展品的藏家和機構 18Chronology 19年表 19Works cited in the descriptions 20Plates 25Introduction Yeung, Chun-tong Yeung, Chun-tong 10展品圖版 25序言 楊春棠 楊春棠 12On Hongshan jade pendants So, Jenny F. So, Jenny F. 14Preface Fung, Sydney Fung, Sydney

Reduction of the spectral linewidth of semiconductor lasers with quantum wire effects—Spectral properties of GaAlAs double heterostructure lasers in high magnetic fields

The spectral linewidth of a GaAlAs double heterostructure laser placed in a high magnetic field is measured at 190 K. It is found that the power-dependent spectral linewidth is reduced by a factor of 0.6 in a magnetic field of 19 T. This reduction is believed to result mainly from the reduction of the linewidth enhancement factor alpha due to a quasi-one-dimensional electronic system formed by the high magnetic field (i.e., by quantum wire effects)

Large-signal dynamics of an ultrafast semiconductor laser at digital modulation rates approaching 10 Gbit/s

High-fidelity pseudorandom digital modulation at 8.2 Gbit/s of an ultrahigh speed semiconductor laser is demonstrated. Studies using simple but representative pulse patterns at 10 Gbit/s give insights into the maximum digital modulation rate attainable from a given laser, as well as relations between large-signal digital performance and small-signal analog response

Intermodulation distortion in a directly modulated semiconductor injection laser

A most important quantity in high-frequency analog transmission is the intermodulation distortion product. Experimental studies of the third order intermodulation distortion products in the modulation response of high-speed semiconductor lasers give very low values (< −60 dB) at low frequencies, an increase at a rate of 40 dB/dec as the modulation frequency is increased, and a leveling off at one-half of the relaxation oscillation resonance frequency. These experimental results can be well explained by a theory based on a perturbative analysis of laser dynamics

Self-sustained picosecond pulse generation in a GaAlAs laser at an electrically tunable repetition rate by optoelectronic feedback

We demonstrate that applying optoelectronic feedback to a high-speed, self-pulsing semiconductor laser is an effective and practical means of generating picosecond optical pulses (~10–20 ps) at a very high repetition rate, between 1 to 5 GHz, which can be electrically tuned. The optical pulses are very stable both on a short term basis with a frequency stability of one part in 10^5, and on the long term basis as a result of the absence of critical optical alignment. This laser system is potentially very useful in high-speed electro-optic signal processing, optical multiplexing, or laser ranging

Enhanced modulation bandwidth of GaAlAs double heterostructure lasers in high magnetic fields: Dynamic response with quantum wire effects

The modulation bandwidth of GaAlAs double heterostructure (DH) lasers in high magnetic fields is measured. We found that the modulation bandwidth is enhanced by 1.4× with a magnetic field of 20 T. This improvement is believed to result from the increase of the differential gain due to two-dimensional carrier confinement effects in the high magnetic field (quantum wire effects). A comparison of the experimental results with a theoretical analysis indicates that the intraband relaxation time tauin of the measured DH laser in the range of 0.1 to 0.2 ps