Single-longitudinal Mode Semiconductor Laser Research Articles

Pulsed dye amplification and frequency doubling of single longitudinal mode semiconductor lasers

A single-longitudinal-mode CW AlGaAs semiconductor laser (786 nm) has been pulse-amplified in a Nd:YAG-pumped dye system by 80 dB, yielding 4-ns (FWHM) infrared pulses having energies of 1.2 mJ. These amplified pulses have then been frequency-doubled in a KDP crystal to yield 110 mu J of tunable ultraviolet radiation at 393 nm. The amplified diode laser linewidth at 786 nm is measured to be 118 MHz. >

1.3 μm distributed feedback laser diode with grating accurately controlled by new fabrication technique

Control of coupling constant κL is a very significant technique for single longitudinal mode semiconductor laser diodes with a grating. κL of distributed feedback laser diodes has been accurately controlled by an MOCVD technique and introduction of a barrier layer.

Relation between chirp and linewidth reduction in external Bragg reflector semiconductor lasers

A 1.5-μm single longitudinal mode semiconductor laser, formed by butt coupling an external Bragg reflector to a standard Fabry–Perot laser, is shown to have greatly reduced wavelength chirp and emission linewidth. The linewidth reduction is found to be proportional to the square of the chirp reduction, in agreement with a previous theoretical prediction. The linewidth and chirp reduction factor can be varied by changing the operating point of the laser. With a 3-mm-long Bragg reflector, a linewidth of 1 MHz at 5 mW has been achieved.

Noise reduction in single longitudinal mode lasers by high-reflectivity coatings

Feedback-induced noise in single longitudinal mode semiconductor lasers was suppressed over a wide range of the amount of the optical feedback light by high-reflectivity facet coatings. A relative intensity noise value was as low as -143 dB/Hz at 3 mW output power under 1 percent of optical feedback in the GaAlAs lasers with high-reflectivity (0.75) facets.

Reduction of feedback-induced noise by high-reflectivity facet coating in single longitudinal mode semiconductor lasers

The feedback-induced noise in single longitudinal mode semiconductor lasers is suppressed over a wide range of feedback light intensity by high-reflectivity facet coatings. A relative intensity noise value was as low as −140 dB/Hz under 1% optical feedback in the GaAlAs lasers with high-reflective (0.75) facets.