Instability of the steady-state regime of generation in laser diodes with a broad gain spectrum

The laser-diode parameters at which the steady-state regime of generation becomes unstable are analyzed within the framework of the mode-locking model. The crucial role of the transverse inhomogeneity of the field, pumping intensity, and spectrum width in developing the instabilities of the steady-state regime of generation is demonstrated. The calculated values of the instability threshold are shown to be consistent with the experimental results. © 2008 Springer Science+Business Media, Inc.

High power, low-jitter encoded picosecond pulse generation using an rf-locked self-q-switched multicontact GaAs/GaAlAs diode laser

The RF locking of a self-Q-switching diode laser is shown to reduce the jitter of a 2.48 GHz train of 1 W peak power picosecond pulses to less than 300 fs. By using direct modulation of the loss in the Q-switched laser, direct encoding of data has been achieved at rates in excess of 2 Gbit/s.

Ultrashort pulse generation in diode lasers

The basic ideas and current state of the art of ultrashort pulse generation by injection lasers are reviewed. All developed techniques, including gain switching, Q-switching, and mode-locking are described and compared. A simple theoretical treatment of a diode laser which emits picosecond light pulses is discussed. Some fundamental limits of the pulse parameters are discussed. Finally, compression of chirped optical pulses by optical fibres and the soliton effect is considered. © 1992 Chapman & Hall.

Adaptive holographic pumping of thin-film organic lasers

In this Letter, we use a reconfigurable hologram to dynamically control the position of incidence of the pump beam onto a liquid-crystal dye-based laser. The results show that there is an increase in the stability of the laser output with time and the average power when compared with the output of the same laser when it is optically excited using a static pump beam. This technique also provides additional functionality, such as wavelength tuning and spatial shaping of the pump beam, both of which are demonstrated here. © 2013 Optical Society of America.

Passive and hybrid mode-locking from a monolithic InGaN/GaN laser diode

We report 4ps and 8ps pulse generation from a two-section monolithic InGaN/GaN laser by hybrid and passive mode-locking, respectively. Pulse trains at a repetition rate of 28.6GHz and an emission wavelength of 422nm are generated. © 2013 The Optical Society.

Local lifetime engineering in 600V pin diode using mix-mode simulation

This paper reports a detailed analysis of the effect of local lifetime killing (LLK) within the drift region on the reverse recovery (RR) characteristics and on-state performance of 600V Silicon PiN diodes. The paper also discusses the influence of the measurement circuit on the reverse recovery of the high voltage diodes and it proposes a simple and effective mix-mode simulation tool for an accurate assessment of the diode performance in reverse recovery mode. © 2013 IEEE.

Superradiant emission from a tapered quantum-dot semiconductor diode emitter

Superradiant emission pulses from a quantum-dot tapered device are generated on demand at repetition rates of up to 5 MHz. The pulses have durations as short as 320 fs at a wavelength of 1270 nm. © 2010 Optical Society of America.

Sub-kHz RF electrical linewidth from a 10GHz passively mode-locked quantum-dot laser diode

A packaged 10GHz monolithic two-section quantum-dot mode-locked laser is presented, with record narrow 500Hz RF electrical linewidth for passive mode-locking. Single sideband noise spectra show 147fs integrated timing jitter over the 4MHz-80MHz frequency range. © 2009 Optical Society of America.

Evidence of quantum lateral confinement in side-gated resonant tunnelling diodes formed by patterned substrate regrowth

MBE regrowth on patterned np-GaAs wafers has been used to fabricate GaAs/AlGaAs double barrier resonant tunnel diodes with a side-gate in the plane of the quantum well. The physical diameters vary from 1 to 20 μm. For a nominally 1 μm diameter diode the peak current is reduced by more than 95% at a side-gate voltage of -2 V at 1.5 K, which we estimate corresponds to an active tunnel region diameter of 75 nm ± 10 nm. At high gate biases additional structure appears in the conductance data. Differential I-V measurements show a linear dependence of the spacing of subsidiary peaks on gate bias indicating lateral quantum confinement. © 1996 American Institute of Physics.

High temperature direct double side cooled inverter module for hybrid electric vehicle application

In this paper a novel approach to the design and fabrication of a high temperature inverter module for hybrid electrical vehicles is presented. Firstly, SiC power electronic devices are considered in place of the conventional Si devices. Use of SiC raises the maximum practical operating junction temperature to well over 200°C, giving much greater thermal headroom between the chips and the coolant. In the first fabrication, a SiC Schottky barrier diode (SBD) replaces the Si pin diode and is paired with a Si-IGBT. Secondly, double-sided cooling is employed, in which the semiconductor chips are sandwiched between two substrate tiles. The tiles provide electrical connections to the top and the bottom of the chips, thus replacing the conventional wire bonded interconnect. Each tile assembly supports two IGBTs and two SBDs in a half-bridge configuration. Both sides of the assembly are cooled directly using a high-performance liquid impingement system. Specific features of the design ensure that thermo-mechanical stresses are controlled so as to achieve long thermal cycling life. A prototype 10 kW inverter module is described incorporating three half-bridge sandwich assemblies, gate drives, dc-link capacitance and two heat-exchangers. This achieves a volumetric power density of 30W/cm3.