Cavity Surface Emitting Diode Laser Research Articles

1.6 kW Yb fiber amplifier using chirped seed amplification for stimulated Brillouin scattering suppression.

In a high power fiber amplifier, a frequency-chirped seed interrupts the coherent interaction between the laser and Stokes waves, raising the threshold for stimulated Brillouin scattering (SBS). Moving the external mirror of a vertical cavity surface-emitting diode laser 0.2μm in 10μs can yield a frequency chirp of 5×1017 Hz/s at a nearly constant output power. Opto-electronic feedback loops can linearize the chirp, and stabilize the output power. The linear variation of phase with time allows multiple amplifiers to be coherently combined using a frequency shifter to compensate for static and dynamic path length differences. The seed bandwidth, as seen by the counter-propagating SBS, also increases linearly with fiber length, resulting in a nearly-length-independent SBS threshold. Experimental results at the 1.6kW level with a 19m delivery fiber are presented. A numerical simulation is also presented.

Atomic clocks and coherent population trapping: Experiments for undergraduate laboratories

We demonstrate how to construct and operate a simple and affordable apparatus for producing coherent effects in atomic vapor and for investigating their applications in time-keeping and magnetometry. The apparatus consists of a vertical cavity surface emitting diode laser directly current-modulated using a tunable microwave oscillator to produce multiple optical fields needed for the observation of coherent population trapping. This effect allows very accurate measurement of the transition frequency between two ground state hyperfine sublevels, which can be used to construct a coherent population trapping-based atomic clock.

Operation of a Passively Mode-Locked Extended-Cavity Surface-Emitting Diode Laser in Multi-GHz Regime

We report on passive mode-locking of vertical cavity surface-emitting diode lasers at 980-nm wavelength, applied to different extended resonator configurations. Stable mode-locking producing pulses of approximately 50 ps in duration at up to 6-GHz repetition rate has been achieved. The use of external feedback results in pronounced harmonic pulse generation, extending the operational range of these new devices.

Picosecond pulse generation from passively modelocked vertical cavity diode laser at up to 15 GHz pulse repetition rate

The generation of ultrashort pulses (∼15 ps) from a passively modelocked InGaAs multiple quantum well (MQW) vertical cavity surface emitting diode laser is reported at a repetition rate up to 15 GHz, utilising a cavity configuration that incorporates a reverse-biased quantum well device as a fast saturable absorber. Pulsing at up to 20 GHz rate has been observed on a continuous-wave background.

Passively modelocked vertical extended cavity surface emitting diode laser

Passive modelocking of a surface emitting diode laser is demonstrated using an extended cavity concept which permits the incorporation of a saturable Bragg reflector mirror into a device designed for large aperture operation as a high-power 980 nm InGaAs multiple quantum-well vertical cavity source.

Dilute nitride based III–V alloys for laser and solar cell applications

The dilute nitrogen alloy GaAs 1− x N x is of recent technological importance for high efficiency solar cells and vertical cavity surface emitting diode lasers used in fiber optic communications. The giant band gap lowering and the abnormal effective mass phenomena observed in this material have been extensively researched. There exist many inconsistencies between the results of various theoretical models and experimental techniques used to probe the above phenomena. It appears that these arise because GaAs 1− x N x should be viewed not as an abnormal alloy but rather as a heavy isoelectronically doped semiconductor.

Hybrid magnetic tunnel junction/vertical cavity surface emitting laser field sensor device

A hybrid magneto-optoelectronic device is demonstrated, composed of a magnetic tunnel junction and a vertical cavity surface emitting diode laser. External magnetic field changes are translated into amplitude modulation of the laser output power with sensitivity that suggests applications in wireless and remote sensing of magnetic fields.