Theory on long time delays, Q-switching and related phenomena in GaAs junction lasers

We present a theory that explains long time delays. Q-switching and related phenomena in GaAs junction lasers, based only on processes known to occur in these lasers.     

Frequency demodulation of a semiconductor laser by FM-AM conversion in an optical fiber

It is theoretically demonstrated that the FM light output of a semiconductor laser can be detected through FM-AM conversion using an optical fiber. The analysis is made in the case of narrow-band FM and for the fundamental mode in a step-index monomode fiber. It is shown that for a 10 GHz modulation frequency, the fiber length necessary to achieve maximum demodulation lies in the range of 10 km.     

Characteristics of bistable CW GaAs junction lasers operating above the delay-transition temperature

The conditions for bistable operation of CW GaAs junction lasers are developed in terms of the previously published double-acceptor trap theory. The experimental CW operation of such devices is shown to agree well with the theoretical results. In addition the fabrication of these bistable lasers is described and several pulsed experiments are reported that indicate a significant increase in the number of trapping centers in the vicinity of the junction.     

Optical repeater using PFM at 1 GHz

We report the first realization of PFM optical communication with a repeater station, using double heterostructure GaAs/GaAlAs semiconductor lasers. The system uses the property of semiconductor lasers for which the optical pulse rate can be locked by an external modulation of the injection current in the vicinity of the resonance frequency of the laser. This modulation scheme has the advantages of a high information rate capability by using the "spiking" resonance of the laser and, more importantly, of a simple repeater station in which another pulsing laser acts as a regenerative pulse amplifier.     

Delays andQswitching in semiconductor lasers--Still an open question

A critical review is made of the available experimental data and the proposed theoretical explanations regarding long delays andQswitching in semiconductor lasers. It is shown that no model is completely satisfactory in explaining all the available data. Guidelines for developing a better theory are presented.     

Frequency stabilization and narrowing of optical pulses from CW GaAs injection lasers

Self-induced intensity pulsations of continuously operating GaAs injection lasers have been frequency stabilized and narrowed by applying to the laser microwave feedback signals derived from the electrical and optical outputs of the laser itself. The width of the optical pulses has been reduced to less than 180 ps at a pulse rate whose spectral width was simultaneously reduced to less than 30 kHz. Significant differences between electrical and optical methods of feedback are demonstrated and discussed.     

Spiking in light pulses from GaAs Q-switched junction lasers

Using a detection system with 150-ps resolution, a spiking behavior has been detected in theQ-switched light output from GaAs junction lasers. At the lower currents in theQ-switching region, a single light spike, whose width is about 300 ps, is observed. At higher currents, additional light spikes appear whose widths and spacings decrease as the current is increased. At the highest pumping levels, only the initial spike is clearly resolved and its width has decreased to less than 200 ps. Qualitative agreement is obtained from a simple theory based on the standard rate equations. The necessary modifications to the theory are discussed and results of computer calculations are presented which predict that the width of the initial spike can be much less than 100 ps at sufficiently high pumping levels.     

Comments on the reliability of GaAs Stripe-Geometry juntion lasers

Experiments with stripe-geometry lasers show that Byer's results for degradation of pulsed diodes can not be generalized to CW conditions. Diodes subjected to CW injection-current density of8 times 10^{3}A/cm²show very little degradation after close to 1000 hours of operation at room temperature.