Semiconductor optical gain

About: Semiconductor optical gain is a research topic. Over the lifetime, 5997 publications have been published within this topic receiving 96505 citations.

Linewidth narrowing and optical phase control of mode-locked semiconductor ring laser employing optical injection locking

Abstract: The linewidth of the individual modes of an actively mode-locked extended-ring-cavity semiconductor laser is reduced from a free running linewidth of over 200-20 kHz by the injection of a narrow linewidth continuous-wave (CW) light. The optical phase of the injection-locked pulses can be controlled by adjusting the free-running optical frequency of the semiconductor ring laser. The variation in the optical phase of the output pulses versus the change of the free-running optical frequency is evaluated to be 0.57/spl pi/ radians within the locking range of about 96 MHz by observing temporal shape of the beat signal formed between output pulses and CW injection light.

High power diode-pumped solid state laser with unstable resonator

Abstract: A large number of semiconductor laser sources coupled with tapered fibers provide a high energy density output for the purpose of longitudinal pumping of a solid state gain medium in an unstable resonator. Each semiconductor laser source generates a beam of radiation at the pump wavelength having characteristic lateral and transverse widths. A plurality of light transmitting fibers, each fiber having an input end and an output end, is coupled with the semiconductor laser sources for delivering the light from a remote location to pump the gain medium. The input end of each fiber has a cross-section substantially matching the transverse and lateral widths of the beams generated by the corresponding semiconductor laser source, and is coupled to receive the beam of radiation generated by a corresponding semiconductor laser source. The output ends of the light transmitting fibers are bundled to deliver the beams coupled into the fibers as a composite light source having a high energy density. Hundreds of watts of pump energy can be delivered to an unstable resonator design with a solid state gain medium from a remotely mounted and cooled array of semiconductor lasers.

High-performance 10 GHz all-active monolithic modelocked semiconductor lasers

Abstract: Using a novel design strategy for the epitaxial structure for monolithic modelocked semiconductor lasers, lasers capable of producing <2 ps pulses at 10 GHz with very low high-frequency jitter have been fabricated in a single growth step.

Finite time of carrier energy relaxation as a cause of optical-power limitation in semiconductor lasers

Abstract: It is shown that the reason why the maximum attainable optical power in semiconductor lasers is limited is the finite time of carrier energy relaxation via scattering by nonequilibrium optical phonons in the quantum-well active region. The power and spectral characteristics of semiconductor lasers are studied experimentally at high excitation levels (up to 100 kA/cm2) in pulsed lasing mode (100 ns, 10 kHz). As the drive current increases, the maximum intensity of stimulated emission tends to a constant value (“saturates”), and the emitted power increases owing to extension of the spectrum to shorter wavelengths. The intensity saturation is due to limitation of the rate of stimulated recombination, caused by a finite time of the electron energy relaxation via scattering by polar optical phonons. It is found that the broadening of the stimulated emission spectrum is related to an increase in carrier concentration in the active region, which enhances the escape of electrons into the waveguide layers. As the drive current increases, the carrier concentration in the waveguide reaches its threshold value and there appears an effective channel of current leakage from the active region. The experiment shows that the appearance of a band of waveguide lasing correlates with a sharp drop in the differential quantum efficiency of a semiconductor laser.

Arrangement for controlling or regulating an emission wavelength and emitted power of a semiconductor laser

Abstract: An arrangement for controlling or regulating the emission wavelength and emitted optical power of a semiconductor laser is provided in optically integrated fashion. The optical power of the laser is at least partially supplied to an optical detector device and to a wavelength selective optical filter device. That part of the supplied power which passes through the filter device is conducted to another opto-electrical detector device. As a result of the two diodes, the optical power and the emission wavelength of the laser are simultaneously measured, whereby two control signals for the injection current of the laser are obtained.