In this work, we study theoretically the dynamical behavior of two semiconductor ring lasers (SRLs). One is subject to negative optoelectronic feedback and the other laser is subject to incoherent optical feedback. Relying on asymptotic methods, we are able to reduce the original set of five equations used to describe the dynamical behavior of SRLs with negative optoelectronic feedback (SRL-NOEF) or incoherent optical feedback (SRL-IOF) to two equations and one map with time delay valid on time-scales longer than the relaxation oscillations (ROs). The equations of the reduced models turn out to be the same for both systems. As we vary the feedback strength, the devices under consideration in this work display both continuous wave operation and a period-doubling route to chaos. The two counter-propagating intensities of both systems exhibit in-phase chaotic behavior for small delay times comparable to the period of relaxation oscillations. For delay times significantly longer than the period of ROs, the two counter-propagating modes show in anti-phase chaotic oscillations. Moreover, for long delay times, we find that the counter-propagating intensities of both systems depict the same dynamical behaviors when their feedback strengths are increased.
In this paper we discuss the use and implementation of on-chip filtered optical feedback in order to tune the emission
wavelength of a semiconductor ring laser. In this device, a directional coupler is used to couple part of the light emitted
by the laser to a feedback section integrated on the same chip. The feedback section contains two arrayed waveguide
gratings and a set of semiconductor optical amplifiers to provide filtering of particular longitudinal modes sustained by
the ring cavity. Each of the two counter-propagating modes supported by the ring laser is coupled back into the same
direction after filtering in the feedback section. We show that, for appropriate currents injected into the semiconductor
optical amplifiers, the emission wavelength can be tuned and that single mode operation in both directions is achieved.
We use a rate equation model in order to demonstrate tuning of the device theoretically.
In this paper we report the design, fabrication, simulation and characterization of a novel discretely
tunable laser based on filtered feedback. This Integrated Filtered-Feedback Tunable Laser (IFF-TL) device
combines a simple and robust switching algorithm with good wavelength stability. It consists of a Fabry-Perot
laser with deeply-etched broadband DBR mirrors. Single mode operation is achieved by using feedback from an
integrated filter. This filter contains an AWG wavelength router and an SOA gate array. A rate equation model
predicts that a properly designed device can switch within 1 ns, while characterization measurements show a
value of only 4 ns. The fast switching and reduced control complexity makes the device very promising for various
advanced applications in optical telecommunication networks.
The goal of investigation is to estimate the quality of the mirror-lens telescope (MLT) consisting of the afocal two-mirror system (ATS) and the lens. Such combination can decrease size and mass of the telescope. This aspect greatly influences the application of device in the outer space. Optical computer programs used nowadays do not allow calculating oblique beams in the systems with surfaces defined parametrically. In the work the task of calculation of oblique beams in such kind of systems was solved and the computer program was composed.