Polarization degenerate solid-state cavity quantum electrodynamics

Quantum Matter and Optic

Submonolayer Quantum Dots for High Speed Surface Emitting Lasers

We report on progress in growth and applications of submonolayer (SML) quantum dots (QDs) in high-speed vertical-cavity surface-emitting lasers (VCSELs). SML deposition enables controlled formation of high density QD arrays with good size and shape uniformity. Further increase in excitonic absorption and gain is possible with vertical stacking of SML QDs using ultrathin spacer layers. Vertically correlated, tilted or anticorrelated arrangements of the SML islands are realized and allow QD strain and wavefunction engineering. Respectively, both TE and TM polarizations of the luminescence can be achieved in the edge-emission using the same constituting materials. SML QDs provide ultrahigh modal gain, reduced temperature depletion and gain saturation effects when used in active media in laser diodes. Temperature robustness up to 100 °C for 0.98 μm range vertical-cavity surface-emitting lasers (VCSELs) is realized in the continuous wave regime. An open eye 20 Gb/s operation with bit error rates better than 10−12has been achieved in a temperature range 25–85 °Cwithout current adjustment. Relaxation oscillations up to ∼30 GHz have been realized indicating feasibility of 40 Gb/s signal transmission

Modeling of modulation distortion in semiconductor laser diodes

An analytical model for harmonic and intermodulation distortion resulting from the direct-current modulation of a laser diode has been developed. The model assumes a polynomial approximation for nonlinearities of the device. For a known input impedance of the laser diode and also for the output termination of the photodiode, the P-P characteristics at the fundamental, harmonic, and intermodulation frequencies can be calculated. The experimental characteristics and calculated characteristics obtained using the developed model for a 1.3-μm DFB (distributed feedback) laser diode at various bias conditions are shown. It can be seen that agreement between the model and experiment is good. The significance of the proposed nonlinear model lies in its simplicity and ease of use in subcarrier multiplexing optical system design, where the level of the intermodulation distortion presents a major limitation

High-performance small vertical-cavity lasers: a comparison of measured improvements in optical and current confinement in devices using tapered apertures

The authors analyze the scaling characteristics of the optical and current confinement for three different vertical-cavity surface-emitting laser (VCSEL) structures with tapered apertures. The improvements in scaling have allowed devices with apertures =150 micro W. The combination of low threshold

Output Power Control and Wavelength Monitoring in Widely Tunable Sampled-Grating DBR Lasers Using Integrated Semiconductor Optical Amplifiers

We report on experimental results obtained for the modal power control and wavelength monitoring in widely tunable (40nm) Sampled-Grating DBR (SGDR) lasers using bias current of monolithically integrated Semiconductor Optical Amplifier (SOA)