Y. Lai

Far-field emission narrowing effect of microdisk lasers

Far-field intensity distribution of semiconductor microdisk lasers is experimentally measured and the emission angle is found to be much smaller than that of a planar source with the same near-field width. In fact the emission angle is determined mainly by the disk radius instead of the disk thickness. A scalar diffraction theory in the cylindrical coordinate is developed to explain such an emission-angle-narrowing phenomenon and numerical calculation based on a vectorial diffraction theory is carried out to explain the measured polarization state.

Mode emission characteristics of semiconductor microdisc and microring lasers

We fabricate both microdisc and microring InGaAsP-InGaAs quantum well semiconductor lasers using an etching-and-bonding technique. Their emission properties are studied by optical pumping at 77 K. Single mode lasing is achieved for discs with a diameter of 5 μm. Multimode emission is observed for rings with larger diameters. Both fundamental and higher order lasing modes are observed and are found to exhibit interesting emission characteristics.

Sub-fs hybrid synchronization between mode-locked fiber lasers

Sub-fs timing synchronization between a 1030nm Yb-doped and a 1560nm Er-doped mode-locked fiber laser is successfully demonstrated by utilizing a hybrid passive/active approach. The physical mechanisms for determining the relative timing jitter are clarified.

A novel S-Shape 1/spl times/2 thermo-optic polymer waveguide switch

We have proposed and analyzed a new type of 1/spl times/2 thermo-optic polymer waveguide switch based on a S-Shape MMI waveguide structure. The device has several advantages compared to conventional thermo-optic waveguide switches that utilize a Mach-Zehnder interferometer, a Y-branch or a straight MMI waveguide. These advantages include: shorter device length, low cross-talk, wide bandwidth, low polarization dependence, low heating power, and digital switching behavior with 6.5 ms switching time. The process tolerance of this device is also larger. All the details of the design and analyses will be given during the conference. We believe this device should find useful applications in future waveguide modules.

Compact S-shape 1/spl times/2 thermo-optic polymer waveguide switch with wide bandwidth

Summary from only given. We propose and analyze a new type of 1 x 2 thermo-optic polymer waveguide switches which have several advantages compared to conventional approaches based on the Mach Zehnder interferometer structure or the Y branch structure. The basic structure of the device is a S-shape multi-mode-interference (MMI) waveguide with less than half of the waveguide being covered by the electric heater.