IEE Proceedings - Optoelectronics
Volume 152, Issue 2, April 2005
Volumes & issues:
Volume 152, Issue 2
April 2005
-
- Author(s): R. Michalzik
- Source: IEE Proceedings - Optoelectronics, Volume 152, Issue 2, page: 57 –57
- DOI: 10.1049/ip-opt:20059042
- Type: Article
- + Show details - Hide details
-
p.
57
(1)
- Author(s): D. Perkins ; P.S. Spencer ; P. Rees
- Source: IEE Proceedings - Optoelectronics, Volume 152, Issue 2, p. 58 –65
- DOI: 10.1049/ip-opt:20045030
- Type: Article
- + Show details - Hide details
-
p.
58
–65
(8)
The authors have developed a polychromatic coupled cavity model for passive optical structures to investigate the underlying ‘cold-cavity’ mode spectrum of active devices, such as semiconductor lasers. The model is validated using a simple Fabry-Perot test structure and then used to study how the mode spectrum of a semiconductor laser subject to external optical feedback is affected by variations in the optical properties of the configuration (in the ‘cold-cavity’ limit). Significant differences in behaviour are observed in the short and long cavity limits, indicating the potentially important role the mode spectrum has in determining the dynamics of such configurations. - Author(s): R. Todt ; Th. Jacke ; R. Laroy ; G. Morthier ; M.-C. Amann
- Source: IEE Proceedings - Optoelectronics, Volume 152, Issue 2, p. 66 –71
- DOI: 10.1049/ip-opt:20045018
- Type: Article
- + Show details - Hide details
-
p.
66
–71
(6)
Device and tuning characteristics of superstructure grating tunable twin-guide (SSG-TTG) laser diodes are presented. The devices are based on the distributed feedback (DFB) TTG laser, but comprise sampled or superstructure gratings in order to utilise Vernier effect tuning to extend the tuning range to potentially several tens of nanometres. In contrast to most other existing monolithic widely tunable semiconductor lasers, this device requires only two tuning currents. The first tuning characteristics show distinct regions of high SMSR where continuous wavelength tuning can be carried out. These regions of high SMSR are spaced in agreement with theoretical predictions that are based on the superstructure grating design. Hence, our observations clearly demonstrate Vernier effect tuning for the first time in a TTG-type laser diode. - Author(s): Th. Jacke ; R. Todt ; M.-C. Amann
- Source: IEE Proceedings - Optoelectronics, Volume 152, Issue 2, p. 72 –76
- DOI: 10.1049/ip-opt:20045031
- Type: Article
- + Show details - Hide details
-
p.
72
–76
(5)
A widely tuneable laser is presented that utilises a vertically-integrated Mach-Zehnder interferometer (VMZ) as a wavelength-selective filter inside the resonator. Among the different design configurations this paper focuses on the ‘separate waveguide’ design that features large confinement factors in the active and tuning region. Calculations show that a tuning range of 80 nm and a side-mode-suppression-ratio (SMSR) of more than 30 dB are feasible for this design. According to the model calculations, corresponding VMZ lasers with different interferometer lengths have been fabricated and analysed with respect to the filter characteristics. The resulting emission spectra show that the filter is well suited to select individually any of the Fabry-Pérot modes out of the gain-limited longitudinal mode spectrum of the resonator. Moreover, a double-VMZ laser is shown that comprises two different interferometers combining the filtering properties of both interferometers. First tuning experiments confirm the Vernier-effect-based tuning mechanism. - Author(s): K.-H. Hasler ; A. Klehr ; H. Wenzel ; G. Erbert
- Source: IEE Proceedings - Optoelectronics, Volume 152, Issue 2, p. 77 –85
- DOI: 10.1049/ip-opt:20045038
- Type: Article
- + Show details - Hide details
-
p.
77
–85
(9)
The dynamic behaviour of long monolithic modelocked lasers for the emission wavelength 1.06 μm containing an active gain section and a passive cavity section was simulated. Numerical tools have been used to solve the travelling wave and carrier rate equations taking into account the effect of gain dispersion. Different configurations and arrangements including an absorber section and a section with a DBR were studied and compared. Best pulses are achieved with a configuration having a saturable-absorber section at the front facet. Peak powers of more than 5 W, pulse energies greater then 15 pJ and time-bandwidth products less than 0.5 are obtained by optimising the resonator configuration. - Author(s): C. Cojocaru ; F. Raineri ; R. Raj ; P. Monnier ; O. Drisse ; L. Legouézigou ; J.-P. Chandouineau ; F. Pommereau ; G.-H. Duan ; A. Levenson
- Source: IEE Proceedings - Optoelectronics, Volume 152, Issue 2, p. 86 –89
- DOI: 10.1049/ip-opt:20045023
- Type: Article
- + Show details - Hide details
-
p.
86
–89
(4)
The first observation, to the authors' knowledge, of laser emission in a defect-free deep-etched 2-dimensional photonic crystal is reported. The structure explored here consists in a triangular lattice of 4.5 μm-deep air holes drilled in a low index contrast InP-based waveguide. Simultaneous guided and vertical directions laser operation is demonstrated at room temperature. A laser threshold of 15 kW/cm2 (average intensity) is measured with a pump diameter corresponding to only 9 periods of the photonic crystal. - Author(s): R.P. Walker ; P. Rees ; I. Pierce ; P.S. Spencer ; G.W. Roberts
- Source: IEE Proceedings - Optoelectronics, Volume 152, Issue 2, p. 90 –96
- DOI: 10.1049/ip-opt:20045032
- Type: Article
- + Show details - Hide details
-
p.
90
–96
(7)
The Lyapunov exponents and plotted bifurcation diagrams for a self-pulsating laser diode under periodic current modulation have been calculated. Different dynamics are obtained dependent on the modulation depth and frequency of the drive current. It is shown that it is very difficult to distinguish between regimes of high periodicity and true chaos. However by introducing a return map relating the pulse peak height and the inter pulse interval clear differences are observed between these regimes. This has consequences for the use of chaotic self-pulsating laser diodes for data encryption applications. - Author(s): M.W. Lee ; P. Rees ; K.A. Shore ; S. Ortin ; L. Pesquera ; A. Valle
- Source: IEE Proceedings - Optoelectronics, Volume 152, Issue 2, p. 97 –102
- DOI: 10.1049/ip-opt:20045025
- Type: Article
- + Show details - Hide details
-
p.
97
–102
(6)
A chaotic semiconductor laser subject to double optical feedback is characterised in terms of the statistical analysis, power spectrum analysis and forecast error analysis of the chaotic dynamics. Varying the relative lengths of the two external cavities, the dynamics are observed and compared to that of a single cavity. We show that in the case of integer multiple external-cavity lengths the round-trip time delays can be deduced from the forecast error analysis. In the case of fractional multiple cavity lengths, only the mean value of the cavity resonance frequencies can be deduced from the power spectra and hence the cavity time delays cannot be found. Cavity time delays that differ more than 0.4 ns can be obtained from the forecast error analysis. In the case of similar cavity lengths, the cavity time delays cannot be extracted. The results show that double optical feedback may offer particular advantages for enhancing security in chaos encryption. - Author(s): S.A. Cripps ; T.J.C. Hosea ; S.J. Sweeney ; D. Lock ; T. Leinonen ; J. Lyytikäinen ; M. Dumitrescu
- Source: IEE Proceedings - Optoelectronics, Volume 152, Issue 2, p. 103 –109
- DOI: 10.1049/ip-opt:20045022
- Type: Article
- + Show details - Hide details
-
p.
103
–109
(7)
The wafer of a 760 nm vertical-cavity surface-emitting laser (VCSEL), designed for oxygen sensing up to high temperatures, is investigated using photomodulated reflectance (PR). By varying the angle of incidence, the VCSEL cavity mode (CM) wavelength is tuned through the positions of two excitonic quantum well (QW) transitions. The PR is also measured over a large temperature range to determine when the QW ground-state transition is tuned with the CM. When tuned, the QW/CM PR lineshape becomes anti-symmetric, as predicted by theory. This occurs at 388 K, where the CM and QW wavelengths coincide at 760.7 nm. It is also observed that when tuned, the CM width measured in the reflectance spectrum is maximised. Temperature dependent device studies are also conducted on a 760 nm edge-emitting laser containing a similar active region as the VCSEL. It is found that up to 250 K the device behaves ideally, with the threshold current being entirely due to radiative recombination. However, as the temperature increases, electron leakage into the indirect X-minima of the barrier and cladding layers becomes increasingly significant. At 300 K, approximately 25% of the threshold current is found to be attributed to electron leakage and this increases to 85% at 388 K. The activation energy for this leakage process is determined to be 255±5 meV, indicating that electron escape from the QWs into the X-minima of the barrier and/or cladding layers is chiefly responsible for the device's poor thermal stability. These results suggest that VCSELs containing this active region are likely to suffer significantly from carrier leakage effects. - Author(s): G. Blume ; T.J.C. Hosea ; S.J. Sweeney ; S.R. Johnson ; J.-B. Wang ; Y.-H. Zhang
- Source: IEE Proceedings - Optoelectronics, Volume 152, Issue 2, p. 110 –117
- DOI: 10.1049/ip-opt:20055024
- Type: Article
- + Show details - Hide details
-
p.
110
–117
(8)
A spectroscopic investigation of GaAsSb/GaAs quantum well (QW) structures grown on GaAs substrates by molecular beam epitaxy is presented. Besides studying their temperature-dependent photoluminescence (PL), the low temperature PL of a series of GaAsSb/GaAs/AlGaAs structures, with varying GaAs spacer thickness is investigated. This latter study was undertaken to investigate the GaAsSb/GaAs band alignment. Blue shifts in the PL peak as a function of excitation laser intensity at a temperature of 10 K for the range of spacer thickness variation are studied. It is observed that significant blue shifting occurs only for spacers thicker than ∼2 nm. It is tentatively suggested that this is indicative of a transition from the electrons and holes being predominantly confined in the same layer (the QW) to being more strongly confined in adjacent layers, as the spacer thickness increases. The angle-dependent photomodulated reflectivity (PR) of similar samples is investigated. Here strong low energy interference oscillations (LEIO) are encountered, which tend to obscure any PR signals arising from the QW. The latter are exploited to estimate the refractive index of the layer responsible for the LEIO, and thus identify it. However, a way to avoid the LEIO is shown, by shortening the laser excitation wavelength, which results in measurable PR signals from the QW region, yielding several QW transition wavelengths. - Author(s): G. Blume ; T.J.C. Hosea ; S.J. Sweeney ; P. de Mierry ; D. Lancefield
- Source: IEE Proceedings - Optoelectronics, Volume 152, Issue 2, p. 118 –124
- DOI: 10.1049/ip-opt:20045020
- Type: Article
- + Show details - Hide details
-
p.
118
–124
(7)
AlGaInN-based resonant-cavity light-emitting diodes (RCLEDs) emitting in the blue at 480 nm are investigated. The electromodulated reflectivity spectra of these devices exhibit a blue shift of the quantum well (QW) feature when it is perturbed with increasing reverse bias pulses. This is due to a reduction of the quantum-confined Stark-effect and this is used to calculate the average piezo-electric field in the QW as 0.62 ± 0.12 MV/cm. Measurements of the light-current characteristics of processed devices between 20 °C and 85 °C and of the modulation bandwidth are also used to characterise the samples and to compare their performance with conventional LEDs. Compared to AlGaInP-based RCLEDs, it is found that the AlGaInN-based RCLEDs are less temperature sensitive, while their modulation characteristics are similar, and better than conventional InGaN-based LEDs. The radiative lifetime was estimated to be 2 ns at a current density of 170 A/cm2. - Author(s): P. Gerlach ; M. Peschke ; C. Hanke ; B.K. Saravanan ; R. Michalzik
- Source: IEE Proceedings - Optoelectronics, Volume 152, Issue 2, p. 125 –130
- DOI: 10.1049/ip-opt:20045029
- Type: Article
- + Show details - Hide details
-
p.
125
–130
(6)
An adapted, simplified simulation tool based on the finite-difference method has been developed which is capable of analysing the high-frequency performance of lumped electroabsorption modulators with stacked dielectric and conductive materials. The impedance, transmission and reflection coefficients in addition to the electro-optical response of two different device layouts are simulated and compared to measurement results. Without any fit parameter, deviations do not exceed 1 dB for frequencies up to 25 GHz which allows detailed device optimisations. - Author(s): V.V. Lysak ; H. Kawaguchi ; I.A. Sukhoivanov
- Source: IEE Proceedings - Optoelectronics, Volume 152, Issue 2, p. 131 –139
- DOI: 10.1049/ip-opt:20045021
- Type: Article
- + Show details - Hide details
-
p.
131
–139
(9)
A new numerical model for calculating the steady-state gain properties of asymmetrical multiple quantum well (MQW) semiconductor optical amplifiers (SOAs) is presented. The model consists of a rate-equation system for carriers in each quantum well, with an integrated gain model. Using this model, the calculated gain spectra and saturation characteristics of an asymmetrical 6-QW SOA are compared with those for symmetrical MQW SOAs. The asymmetrical MQW SOA is found to have a gain bandwidth of about 137 nm and a saturation power of −8.8 dB m at 202 mA, both greater than conventional symmetrical MQW SOAs at the same gain. - Author(s): W.K. Ng ; C.H. Tan ; P.A. Houston ; A. Krysa
- Source: IEE Proceedings - Optoelectronics, Volume 152, Issue 2, p. 140 –144
- DOI: 10.1049/ip-opt:20045015
- Type: Article
- + Show details - Hide details
-
p.
140
–144
(5)
An evanescently coupled side-illuminated waveguide phototransistor to improve on power handling and coupling efficiency over vertically illuminated photodetectors was demonstrated. The Al composition in the AlxIn(1-x-y)GayAs passive waveguide was tailored for optimised optical confinement and coupling into the InGaAs absorption region. The presence of a passive waveguide as well as the internal transistor gain in the waveguide phototransistor showed an improvement in responsivity that was 300 times more than a p-i-n diode of similar structure to the base–collector junction.
Editorial: Semiconductor optoelectronics
Polychromatic coupled cavity model of passive structures
Demonstration of Vernier effect tuning in tunable twin-guide laser diodes
Buried heterostructure laser with vertically-integrated Mach-Zehnder interferometer for Vernier-effect-based wide wavelength tuning
Simulation of high-power pulse generation due to modelocking in long multisection lasers
Room-temperature simultaneous in-plane and vertical laser operation in a deep-etched InP-based two-dimensional photonic crystal
Analysis of chaos generated by a modulated self-pulsating laser diode
Dynamical characterisation of laser diode subject to double optical feedback for chaotic optical communications
High temperature operation of 760 nm vertical-cavity surface-emitting lasers investigated using photomodulated reflectance wafer measurements and temperature-dependent device studies
Spectroscopic investigations of GaAsSb/GaAs based structures for 1.3 μm VCSEL applications
AlGaInN resonant-cavity LED devices studied by electromodulated reflectance and carrier lifetime techniques
High-frequency analysis of laser-integrated lumped electroabsorption modulators
Gain spectra and saturation power of asymmetrical multiple quantum well semiconductor optical amplifiers
High current InP/InGaAs evanescently coupled waveguide phototransistor
Most viewed content for this Journal
Article
content/journals/ip-opt
Journal
5
Most cited content for this Journal
We currently have no most cited data available for this content.