Two-wavelength switching with a distributed-feedback semiconductor optical amplifier (DFBSOA)

Abstract

Switching of a signal beam by another control beam at different wavelength is demonstrated experimentally using the optical bistability occurring in a 1.55 |Jim-distributed feedback semiconductor optical amplifier (DFBSOA) working in reflection. Counterclockwise (S-shaped) and reverse (clockwise) bistability are observed in the output of the control and the signal beam respectively, as the power of the input control signal is increased. With this technique an optical signal can be set in either of the optical input wavelengths by appropriate choice of the powers of the input signals. The switching properties of the DFBSOA are studied experimentally as the applied bias current is increased from below to above threshold and for different levels of optical power in the signal beam and different wavelength detunings between both input signals. Higher on-off extinction ratios, wider bistable loops and lower input power requirements for switching are obtained when the DFBSOA is operated slightly above its threshold value.

Power and wavelength polarization bistability with very wide hysteresis cycles in a 1550nm-VCSEL subject to orthogonal optical injection

“…Figures 3(a) and 3(b) show that for both polarization modes of the device, as the applied bias current is increased well above threshold the more power is needed for the obtaining of optical bistability and also the width of the associated hysteresis cycles widen considerably. This behavior is the same as that observed for dispersive bistability in Vertical-Cavity Semiconductor Optical Amplifiers [21] and also in planar devices, including Fabry-Perot [22] and distributed feedback semiconductor laser amplifiers [23]. We believe therefore that the dispersive nonlinearity is also the physical phenomenon that explains the widening of the hysteresis cycles associated with the occurrence of PB as the bias current is increased well above threshold.…”

Analysis on wavelength bistability properties of vertical cavity semiconductor optical amplifier

“…The appearance condition of wavelength bistability is derived and the factor including pump current density, top DBRs reflective and input optical power affecting wavelength bistable loop width is analyzed. Furthermore, the methods how to control the wavelength bistability loop width are proposed [1][2][3][4].…”

Switching Behavior of Bistable DFB Semiconductor Laser Amplifiers

“…Then, Hurtado et al, by the same technique, presented a broad-band all-optical logic gate [10]. In another report, using a bistable DFB-SLA, Hurtado described a two-wavelength switch [11]. Meanwhile, distorting effects of phase shift and chirp on the falling edge of the output pulse of a bistable DFB-SLA were analyzed by Wu et al [12].…”