Non-linear dynamics of multimode semiconductor lasers: dispersion-based phase instability and route to single-frequency operation.

Emission dynamics of a multimode broadband interband semiconductor laser have been investigated experimentally and theoretically. Non-linear dynamics of a III-V semiconductor quantum well surface-emitting laser reveal the existence of a modulational instability, observed in the anomalous dispersion regime. An additional unstable region arises in the normal dispersion regime, owing to carrier dynamics, and has no analogy in systems with fast gain recovery.

Semiconductor disk laser in bi-frequency operation by laser ablation micromachining of a laser mirror.

We present bi-frequency continuous wave oscillation in a semiconductor disk laser through direct writing of loss-inducing patterns onto an intra-cavity high reflector mirror. The laser is a Vertical External Cavity Surface Emitting Laser which is optically pumped by up to 1.1 W of 808 nm light from a fibre coupled multi-mode diode laser, and oscillates on two Hermite-Gaussian spatial modes simultaneously, achieving wavelength separations between 0.

High-power tunable low-noise coherent source at 1.06 μm based on a surface-emitting semiconductor laser.

Exploiting III-V semiconductor technologies, vertical external-cavity surface-emitting laser (VECSEL) technology has been identified for years as a good candidate to develop lasers with high power, large coherence, and broad tunability. Combined with fiber amplification technology, tunable single-frequency lasers can be flexibly boosted to a power level of several tens of watts. Here, we demonstrate a high-power, single-frequency, and broadly tunable laser based on VECSEL technology.

Vortex Laser based on III-V semiconductor metasurface: direct generation of coherent Laguerre-Gauss modes carrying controlled orbital angular momentum.

The generation of a coherent state, supporting a large photon number, with controlled orbital-angular-momentum L = ħl (of charge l per photon) presents both fundamental and technological challenges: we demonstrate a surface-emitting laser, based on III-V semiconductor technology with an integrated metasurface, generating vortex-like coherent state in the Laguerre-Gauss basis. We use a first order phase perturbation to lift orbital degeneracy of wavefunctions, by introducing a weak anisotropy called here "orbital birefringence", based on a dielectric metasurface. The azimuthal symmetry breakdown and non-linear laser dynamics create "orbital gain dichroism" allowing selecting vortex handedness.

Coherent continuous-wave dual-frequency high-Q external-cavity semiconductor laser for GHz-THz applications.

We report a continuous-wave highly-coherent and tunable dual-frequency laser emitting at two frequencies separated by 30 GHz to 3 THz, based on compact III-V diode-pumped quantum-well surface-emitting semiconductor laser technology. The concept is based on the stable simultaneous operation of two Laguerre-Gauss transverse modes in a single-axis short cavity, using an integrated sub-wavelength-thick metallic mask. Simultaneous operation is demonstrated theoretically and experimentally by recording intensity noises and beat frequency, and time-resolved optical spectra.

Self-mixing in low-noise semiconductor vortex laser: detection of a rotational Doppler shift in backscattered light.

Light carrying orbital angular momentum L⃗, scattered by a rotating object at angular velocity Ω⃗, experiences a rotational Doppler shift Ω⃗·L⃗. We show that this fundamental light-matter interaction can be detected exploiting self-mixing in a vortex laser under Doppler-shifted optical feedback, with quantum noise-limited light detection. We used a low-noise relaxation oscillation-free (class-A) vortex laser, based on III-V semiconductor vertical-external-cavity-surface-emitting laser technology to generate coherent Laguerre-Gauss beams carrying L=ℏl (l=±1,…±4).

Experimental demonstration of a tunable dual-frequency semiconductor laser free of relaxation oscillations.

Tunable dual-frequency oscillation is demonstrated in a vertical external-cavity surface-emitting laser. Simultaneous and robust oscillation of the two orthogonally polarized eigenstates is achieved by reducing their overlap in the optical active medium. The class-A dynamics of this laser, free of relaxation oscillations, enables one to suppress the electrical phase noise in excess that is usually observed in the vicinity of the beat note.

Single-frequency external-cavity semiconductor ring-laser gyroscope.

We report for the first time (to our knowledge) the experimental achievement of a single-frequency ring-laser gyroscope using a diode-pumped half-vertical-cavity semiconductor-emitting laser structure as a gain medium. Thanks to the control of mode competition by an active feedback loop, we observe a beat signal from recombined beams that has a frequency proportional to the rotation rate as predicted by the Sagnac effect. This promising result opens new perspectives for rotation sensing.

Shot-noise-limited operation of a monomode high-cavity-finesse semiconductor laser for microwave photonics applications.

Shot-noise-limited laser operation over a wide spectral bandwidth is demonstrated by using a semiconductor active medium inserted into a high-Q external cavity. This approach ensures, with a compact design, a sufficiently long photon lifetime to reach the oscillation-relaxation-free class A regime. The laser relative intensity noise is limited to the shot-noise relative floor, -156 dB/Hz for a 1 mA detected photocurrent, over the 100 MHz to 18 GHz bandwidth.

Single-frequency Sb-based distributed-feedback lasers emitting at 2.3 microm above room temperature for application in tunable diode laser absorption spectroscopy.

GaInAsSb/GaAlAsSb/GaSb distributed-feedback (DFB) laser diodes based on a type I active region were fabricated by molecular beam epitaxy at the Centre d'Electronique et de Micro-Optoélectronique de Montpellier (CEM2). The DFB processing was done by Nanoplus Nanosystems and Technologies GmbH. The devices work in the continuous-wave regime above room temperature around an emission wavelength of 2.

Continuous-wave operation of monolithically grown 1.5-microm optically pumped vertical-external-cavity surface-emitting lasers.

Continuous-wave operation, to as high as 7 degrees C, of 1.5-microm optically pumped vertical-external-cavity surface-emitting lasers is reported. The epitaxial structure, monolithically grown on InP by metal-organic chemical vapor deposition, consists of an InAlAs/GaInAlAs Bragg reflector, an InGaAs/InGaAsP active region, and an InP capping layer.