Abstract:Abstract:We study experimentally the dynamics of quantum-dot (QD) passively mode-locked semiconductor lasers under external optical injection. The lasers demonstrated multiple dynamical states, with bifurcation boundaries that depended upon the sign of detuning variation. The area of the hysteresis loops grew monotonically at small powers of optical injection and saturated at moderate powers. At high injection levels the hysteresis decreased and eventually disappeared.
“…However, the unlocking point is achieved at a lower value of injected power of 104.9 μW yielding a region of bistability with an associated hysteresis cycle. For details on the optical bistable regimes in QDMLLs under external optical injection see 27 ). Figure 3 (i) QDMLL’s spectral peak power vs optical input power for increasing (red) and decreasing (blue) injection strength.…”
Section: Resultsmentioning
confidence: 99%
“…3(ii) reveals that under strong enough external optical injection (481 μW), the mode-locked spectrum is suppressed and replaced by a single peak where the QDMLL is injection-locked to the external signal. As a result of the injection-locking the pulsating output is substituted by a constant optical emission characteristic of injection-locking behavior 27 . These results therefore clearly demonstrate that simply by controlling the injection strength the system can be driven either in unlocked or injection-locked regimes with clearly different temporal characteristics.…”
Section: Resultsmentioning
confidence: 99%
“…The effect of external optical injection in QDMLLs has also undergone substantial research effort recently 25 – 30 . Occurrence of different dynamical regimes as well as bistable operation has been reported in QDMLLs under single and double optical injection schemes 26 , 27 . Moreover, reduced noise operation, lower pulse jitter, narrower RF linewidths and repetition rate tuning (up to hundreds of MHz) have also been achieved in Q-Dash 31 – 33 and QDMLLs 28 , 29 by means of external optical injection.…”
Controlled generation and inhibition of externally-triggered picosecond optical pulsating regimes are demonstrated experimentally in a quantum dot mode locked laser (QDMLL) subject to external injection of an amplitude modulated optical signal. This approach also allows full control and repeatability of the time windows of generated picosecond optical pulses; hence permitting to define precisely their temporal duration (from <1 ns spans) and repetition frequency (from sub-Hz to at least hundreds of MHz). The use of a monolithic QDMLL, operating at 1300 nm, provides a system with a very small footprint that is fully compatible with optical telecommunication networks. This offers excellent prospects for use in applications requiring the delivery of ultrashort optical pulses at precise time instants and at tunable rates, such as optical imaging, time-of-flight diagnostics and optical communication systems.
“…However, the unlocking point is achieved at a lower value of injected power of 104.9 μW yielding a region of bistability with an associated hysteresis cycle. For details on the optical bistable regimes in QDMLLs under external optical injection see 27 ). Figure 3 (i) QDMLL’s spectral peak power vs optical input power for increasing (red) and decreasing (blue) injection strength.…”
Section: Resultsmentioning
confidence: 99%
“…3(ii) reveals that under strong enough external optical injection (481 μW), the mode-locked spectrum is suppressed and replaced by a single peak where the QDMLL is injection-locked to the external signal. As a result of the injection-locking the pulsating output is substituted by a constant optical emission characteristic of injection-locking behavior 27 . These results therefore clearly demonstrate that simply by controlling the injection strength the system can be driven either in unlocked or injection-locked regimes with clearly different temporal characteristics.…”
Section: Resultsmentioning
confidence: 99%
“…The effect of external optical injection in QDMLLs has also undergone substantial research effort recently 25 – 30 . Occurrence of different dynamical regimes as well as bistable operation has been reported in QDMLLs under single and double optical injection schemes 26 , 27 . Moreover, reduced noise operation, lower pulse jitter, narrower RF linewidths and repetition rate tuning (up to hundreds of MHz) have also been achieved in Q-Dash 31 – 33 and QDMLLs 28 , 29 by means of external optical injection.…”
Controlled generation and inhibition of externally-triggered picosecond optical pulsating regimes are demonstrated experimentally in a quantum dot mode locked laser (QDMLL) subject to external injection of an amplitude modulated optical signal. This approach also allows full control and repeatability of the time windows of generated picosecond optical pulses; hence permitting to define precisely their temporal duration (from <1 ns spans) and repetition frequency (from sub-Hz to at least hundreds of MHz). The use of a monolithic QDMLL, operating at 1300 nm, provides a system with a very small footprint that is fully compatible with optical telecommunication networks. This offers excellent prospects for use in applications requiring the delivery of ultrashort optical pulses at precise time instants and at tunable rates, such as optical imaging, time-of-flight diagnostics and optical communication systems.
“…We use a delay differential model of a passively mode-locked laser proposed in [51]. This delay differential system has been extensively applied to analyze instabilities [38,41] and hysteresis [21,43] in mode-locked lasers, optically injected lasers [2,45], hybrid mode locking [3], noise reduction [25], resonance to delayed feedback [1], and Fourier domain mode locking [46]. The same system has been used to model four identical lasers coupled in D 4 -symmetric fashion [44].…”
The goal of this paper is to study the equivariant Hopf bifurcation of relative periodic solutions from relative equilibria in a system of five identical passively mode-locked semiconductor lasers coupled in the S 5-equivariant fashion. Each laser is described by a delay differential model respecting a spacial S 1-symmetry. The existence of branches of relative periodic solutions together with their symmetric classification is established using the equivariant twisted S 5 × S 1-degree with one free parameter. Theoretical results are supported by numerical simulations.
“…16 Stable injection-locking with no instabilities observed at zero detuning frequency has been demonstrated in QD single section and PMLLs. [17][18][19] These observations suggest that the noise characteristics of QD hybrid mode-locked lasers (HMLLs) could be further improved by optical injection seeding.…”
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