Diode laser pumped, KERR phase-shifting and switching of a diode laser signal in a small area optical fibre

In this paper authors report the first demonstration of a diode laser powered Kerr effect device, consisting of a single birefringent fiber, able to phase-shift and switch an optical signal generated by a second laser diode. They have obtained fast, stable phase-shifting of 90° in a single fiber, at a coupled pump power of only 20 mW. Using this phase shift to induce polarization switching with resultant gating, 25% modulation of the diode laser signal has been observed, with a detection limited-rise time of 10ns.

First demonstration of two photon absorption in a semiconductor waveguide pumped by a diode laser

For the first time, lasers have been used to induce a fast all-optical nonresonant nonlinearity at wavelengths well beyond the band edge in a GaAs/GaAlAs multiquantum well waveguide. Using a Q-switched diode laser, which gave optical pulses of 3.5 ps duration and 7 W peak power, an intensity-dependent transmission was recorded that was consistent with the presence of two photon absorption in the waveguide. The measured two photon absorption coefficient was 11 ± 2cm/GW.

Ultrashort pulse generation in diode laser devices

The generation of ultrashort optical pulses by semiconductor lasers has been extensively studied for many years. A number of methods, including gain-/Q-switching and different types of mode locking, have been exploited for the generation of picosecond and sub-picosecond pulses [1]. However, the shortest pulses produced by diode lasers are still much longer and weaker than those that are generated by advanced mode-locked solid-state laser systems [2]. On the other hand, an interesting class of devices based on superradiant emission from multiple contact diode laser structures has also been recently reported [3]. Superradiance (SR) is a transient quantum optics phenomenon based on the cooperative radiative recombination of a large number of oscillators, including atoms, molecules, e-h pairs, etc. SR in semiconductors can be used for the study of fundamental properties of e-h ensembles such as photon-mediated pairing, non-equilibrium e-h condensation, BSC-like coherent states and related phenomena. Due to the intrinsic parameters of semiconductor media, SR emission typically results in the generation of a high-power optical pulse or pulse train, where the pulse duration can be much less than 1 ps, under optimised bias conditions. Advantages of this technique over mode locking in semiconductor laser structures include potentially shorter pulsewidths and much larger peak powers. Moreover, the pulse repetition rate of mode-locked pulses is fixed by the cavity round trip time, whereas the repetition rate of SR pulses is controlled by the current bias and can be varied over a wide range. © 2012 IEEE.

Superradiant emission in semiconductor diode laser structures

This paper reviews recent advances in superradiant (SR) emission in semiconductors at room temperature, a process which has been shown to enable the generation on demand of high power picosecond or subpicosecond pulses across a range of different wavelengths. The different characteristic features of SR emission from semiconductor devices with bulk, quantum-well, and quantum-dot active regions are outlined, and particular emphasis is placed on comparing the characteristic features of SR with those of lasing. Finally, potential applications of SR pulses are discussed. © 1995-2012 IEEE.

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.

Spectral measurement of diode lasers with a single-mode birefringent fibre

A new, and very simple spectrometer based on birefringent fiber is described. A resolution of 0.02 angstrom has been achieved, and the system has been used to measure diode laser chirp. A length of 10km of fiber would be sufficient to resolve single mode line widths.

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.

Low power all-optical switch in a passive InGaAsP multiple quantum well waveguide

We demonstrate the use of resonant bandfilling nonlinearity in an InGaAsP/InGaAsP Multiple Quantum Well (MQW) waveguide due to photogenerated carriers to obtain switching at pulse powers, which can readily be obtained from an erbium amplified diode laser source. In order to produce gating a polarisation rotation gate was used, which relies on an asymmetry in the nonlinear refraction on the principle axes of the waveguide.