Laser diode arrays are inexpensive, compact, efficient, and reliable light sources. However, the output beam, which is highly elliptical, is difficult to both efficiently collect and concentrate. This has limited continuous wave (CW) diode sources to power levels under 100 Watts. The fast axis of the laser diode array output tends to have good beam quality, M2~ 2, and a source size of ~ 1 um. The slow axis of laser diode broad stripes and of array bars is highly multimode, typically having an angular distribution of 10 degrees at the 1/e2 power points. The slow axis beam quality for a 500 um wide stripe is thus M2~ 70, and M2~ 1400 for a one centimeter array. One means of improving the brightness is to individually fiber couple broad stripe diodes, and then bundle the fiber ends together. Another is to collimate the fast axis of one centimeter arrays using a fiber lens1, and then fiber couple into a linear array of fibers. The output ends of the fibers are also bundled together. Both techniques are compact and relatively simple, and power is scaled by increasing the number of fibers in the bundle. M2 ~ 350 are available at 60 Watts output using the latter technique. It is difficult to scale beyond 100 Watts without increasing M2 to values greater than 500. This is due to loss of brightness in fiber coupling, as an essentially linear source is being coupled into a round fiber, or in mode mixing as light propagates through the fiber. Brightness is further reduced in fiber bundling by the presence of the fiber cladding, and by the less than unity packing factor of round fibers.
{"title":"Non-imaging Laser Diode Array Beam Shaper","authors":"D. Caffey, W. Clarkson","doi":"10.1364/slada.1995.mc.4","DOIUrl":"https://doi.org/10.1364/slada.1995.mc.4","url":null,"abstract":"Laser diode arrays are inexpensive, compact, efficient, and reliable light sources. However, the output beam, which is highly elliptical, is difficult to both efficiently collect and concentrate. This has limited continuous wave (CW) diode sources to power levels under 100 Watts. The fast axis of the laser diode array output tends to have good beam quality, M2~ 2, and a source size of ~ 1 um. The slow axis of laser diode broad stripes and of array bars is highly multimode, typically having an angular distribution of 10 degrees at the 1/e2 power points. The slow axis beam quality for a 500 um wide stripe is thus M2~ 70, and M2~ 1400 for a one centimeter array. One means of improving the brightness is to individually fiber couple broad stripe diodes, and then bundle the fiber ends together. Another is to collimate the fast axis of one centimeter arrays using a fiber lens1, and then fiber couple into a linear array of fibers. The output ends of the fibers are also bundled together. Both techniques are compact and relatively simple, and power is scaled by increasing the number of fibers in the bundle. M2 ~ 350 are available at 60 Watts output using the latter technique. It is difficult to scale beyond 100 Watts without increasing M2 to values greater than 500. This is due to loss of brightness in fiber coupling, as an essentially linear source is being coupled into a round fiber, or in mode mixing as light propagates through the fiber. Brightness is further reduced in fiber bundling by the presence of the fiber cladding, and by the less than unity packing factor of round fibers.","PeriodicalId":365685,"journal":{"name":"Semiconductor Lasers Advanced Devices and Applications","volume":"71 4","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"113959749","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.1364/slada.1995.tuc.5
P. Chazan, J. Ralston
Recent interest in high-power single-mode diode lasers has led to the evaluation of a variety of semiconductor amplifier geometries [1], integrated master oscillator power amplifier (MOPA), designs and flared oscillator devices. Flared amplifiers and oscillators have been found to be less sensitive to filamentation effects than broad area devices, although filamentation still ultimately limits the performance of such devices [2]. Using a FD-BPM model we investigate the performance to be expected from various flared laser structures in terms of both output power and beam quality. We clarify the influence of such material parameters as the number of quantum wells, the differential quantum efficiency and the linewidth enhancement factor on the output beam profile of the amplifier. We point out the influence of the linewidth enhancement factor showing that a reduction of this factor improves the output beam quality, the resistance to inhomogeneous injection, and the output farfield. Furthermore, a simulation of a 2D integrated elliptical lens is presented, showing the possibility of ‘on chip’ correction of the astigmatism for low α-factor structures. Such a lens would spare the use of an external cylindrical lens for collimation of the output signal.
{"title":"Beam Propagation Model of Tapered Amplifiers including Non-Linear Gain and Carrier Diffusion","authors":"P. Chazan, J. Ralston","doi":"10.1364/slada.1995.tuc.5","DOIUrl":"https://doi.org/10.1364/slada.1995.tuc.5","url":null,"abstract":"Recent interest in high-power single-mode diode lasers has led to the evaluation of a variety of semiconductor amplifier geometries [1], integrated master oscillator power amplifier (MOPA), designs and flared oscillator devices. Flared amplifiers and oscillators have been found to be less sensitive to filamentation effects than broad area devices, although filamentation still ultimately limits the performance of such devices [2]. Using a FD-BPM model we investigate the performance to be expected from various flared laser structures in terms of both output power and beam quality. We clarify the influence of such material parameters as the number of quantum wells, the differential quantum efficiency and the linewidth enhancement factor on the output beam profile of the amplifier. We point out the influence of the linewidth enhancement factor showing that a reduction of this factor improves the output beam quality, the resistance to inhomogeneous injection, and the output farfield. Furthermore, a simulation of a 2D integrated elliptical lens is presented, showing the possibility of ‘on chip’ correction of the astigmatism for low α-factor structures. Such a lens would spare the use of an external cylindrical lens for collimation of the output signal.","PeriodicalId":365685,"journal":{"name":"Semiconductor Lasers Advanced Devices and Applications","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125533240","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.1364/slada.1995.tuc.6
Z. Dai, R. Michalzik, P. Unger
To design an optimized high-power semiconductor traveling wave amplifier (TWA), it is important to study the parameter dependencies of a TWA on its waveguide structure, material properties, and operating conditions. Since the degradation of the output beam profile in a broad-stripe TWA is often observed in practice, two-dimensional models employing the beam propagation method (BPM) and the effective index method have been widely used [1-2]. These models are usually based on a linearization of basic material properties. For high-power TWAs, the operating current is several times larger than the threshold current of a corresponding laser diode. Linear approximations are under these conditions no longer valid. In this paper, we consider nonlinear material properties in a self-consistent BPM model. Nonlinear gain and residual facet reflectivities are found to greatly influence the operating characteristics of the devices.
{"title":"Operating Characteristic Simulation of High-Power Broad-Stripe Quantum-Well Semiconductor Traveling Wave Amplifiers","authors":"Z. Dai, R. Michalzik, P. Unger","doi":"10.1364/slada.1995.tuc.6","DOIUrl":"https://doi.org/10.1364/slada.1995.tuc.6","url":null,"abstract":"To design an optimized high-power semiconductor traveling wave amplifier (TWA), it is important to study the parameter dependencies of a TWA on its waveguide structure, material properties, and operating conditions. Since the degradation of the output beam profile in a broad-stripe TWA is often observed in practice, two-dimensional models employing the beam propagation method (BPM) and the effective index method have been widely used [1-2]. These models are usually based on a linearization of basic material properties. For high-power TWAs, the operating current is several times larger than the threshold current of a corresponding laser diode. Linear approximations are under these conditions no longer valid. In this paper, we consider nonlinear material properties in a self-consistent BPM model. Nonlinear gain and residual facet reflectivities are found to greatly influence the operating characteristics of the devices.","PeriodicalId":365685,"journal":{"name":"Semiconductor Lasers Advanced Devices and Applications","volume":"79 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125692109","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.1364/slada.1995.tua.2
P. Landais, G. Pham, G. Duan, C. Chabran, P. Gallion, J. Jacquet
Clock recovery is a major key function of any transmission systems. All-optical devices are very attractive due to their high speed and their simplicity as electro-optic conversion is not necessary. It has been shown experimentally that the self-pulsation (SP) in a multielectrode distributed feedback (DFB) laser can be synchronised to the data clock rate of an incoming optical return to zero (RZ) signal. This property makes SP lasers (SPL) good candidates for clock recovery in transmission systems. Jinno et al. [1] have shown a clock extraction at 200 Mbit/s and Barnsley et al. [2] at 5 Gbit/s. They both have used multielectrode SPL with one section operated as saturable absorber section, which limits SP frequency due to the limitation of carrier lifetime. Feiste et al. [3] have extracted 18 GHz clock by using a SP DFB laser without saturable absorber. We can note that in these experiments, the clock recovery occurs in injection locking conditions where the wavelength of the injected optical signal is nearly identical to the SPL wavelength. Despite the fact that such configuration allows optical carrier recovery with a few µW injected, it seriously limits the application of the SPL to clock recovery. This paper reports for the first time that a 3.8 GHz clock extraction with low time-jitter can be obtained even under conditions of large wavelength difference.
{"title":"4 GHz All-Optical Clock Recovery Using a Self-Pulsating Multielectrode Distributed Feedback Laser","authors":"P. Landais, G. Pham, G. Duan, C. Chabran, P. Gallion, J. Jacquet","doi":"10.1364/slada.1995.tua.2","DOIUrl":"https://doi.org/10.1364/slada.1995.tua.2","url":null,"abstract":"Clock recovery is a major key function of any transmission systems. All-optical devices are very attractive due to their high speed and their simplicity as electro-optic conversion is not necessary. It has been shown experimentally that the self-pulsation (SP) in a multielectrode distributed feedback (DFB) laser can be synchronised to the data clock rate of an incoming optical return to zero (RZ) signal. This property makes SP lasers (SPL) good candidates for clock recovery in transmission systems. Jinno et al. [1] have shown a clock extraction at 200 Mbit/s and Barnsley et al. [2] at 5 Gbit/s. They both have used multielectrode SPL with one section operated as saturable absorber section, which limits SP frequency due to the limitation of carrier lifetime. Feiste et al. [3] have extracted 18 GHz clock by using a SP DFB laser without saturable absorber. We can note that in these experiments, the clock recovery occurs in injection locking conditions where the wavelength of the injected optical signal is nearly identical to the SPL wavelength. Despite the fact that such configuration allows optical carrier recovery with a few µW injected, it seriously limits the application of the SPL to clock recovery. This paper reports for the first time that a 3.8 GHz clock extraction with low time-jitter can be obtained even under conditions of large wavelength difference.","PeriodicalId":365685,"journal":{"name":"Semiconductor Lasers Advanced Devices and Applications","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134321456","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.1364/slada.1995.tue.2
A. Egan, P. Rees, J. O'Gorman, J. Hegarty, G. Farrell, P. Phelan
Higher speed requirements in communication systems have led to demands for fast optical sub-systems. Important aspects of such sub-systems will be the synchronization of self-pulsating laser diode (SP LD) emission to electrical or optical signals and timing extraction, aspects which have already been demonstrated experimentally. Consequently, these devices may play important roles as functional elements in transparent transmission systems. Effective implementation of these functions in communications systems using these devices depends on a more complete understanding of synchronization of SP LDs than exists at present. In this paper we address a number of important timing issues relating to electro-optical synchronization. We have experimentally observed for the first time that a phase difference exists between the input electrical signal and the output optical signal of a synchronized SP LD and we have experimentally and theoretically investigated the nature and behaviour of this phase difference. We have also numerically investigated the impact of synchronization of SP LDs on timing jitter in the emitted optical pulses.
{"title":"Dynamics of electro-optical synchronization of self-pulsating laser diodes","authors":"A. Egan, P. Rees, J. O'Gorman, J. Hegarty, G. Farrell, P. Phelan","doi":"10.1364/slada.1995.tue.2","DOIUrl":"https://doi.org/10.1364/slada.1995.tue.2","url":null,"abstract":"Higher speed requirements in communication systems have led to demands\u0000 for fast optical sub-systems. Important aspects of such sub-systems\u0000 will be the synchronization of self-pulsating laser diode (SP LD)\u0000 emission to electrical or optical signals and timing extraction,\u0000 aspects which have already been demonstrated experimentally.\u0000 Consequently, these devices may play important roles as functional\u0000 elements in transparent transmission systems. Effective implementation\u0000 of these functions in communications systems using these devices\u0000 depends on a more complete understanding of synchronization of SP LDs\u0000 than exists at present. In this paper we address a number of important\u0000 timing issues relating to electro-optical synchronization. We have\u0000 experimentally observed for the first time that a phase difference\u0000 exists between the input electrical signal and the output optical\u0000 signal of a synchronized SP LD and we have experimentally and\u0000 theoretically investigated the nature and behaviour of this phase\u0000 difference. We have also numerically investigated the impact of\u0000 synchronization of SP LDs on timing jitter in the emitted optical\u0000 pulses.","PeriodicalId":365685,"journal":{"name":"Semiconductor Lasers Advanced Devices and Applications","volume":"209 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122370293","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Y. Yakovlev, K. Moiseev, M. Mikhailova, O. G. Ershov
We present a new physical approach to design of III-V middle-infrared diode lasers which can lead to increasing operating temperature of InAs-based lasers. Main pecularity of proposed method is using interface radiative recombination of spatially-separated carriers in type II broken-gap p-p heterojunctions (HJs). Lattice-machted nondoped and doped GaIn0.17As0.22Sb layers with high quality interface were grown on p-InAs (100). It was established that GaIn0.17As0.22Sb/InAs HJ is type II with broken-gap alignment.
{"title":"Tunnel-Injection Laser Based on Type II Broken-Gap p-GaInAsSb/p-InAs Single Heterojunction","authors":"Y. Yakovlev, K. Moiseev, M. Mikhailova, O. G. Ershov","doi":"10.1364/slada.1995.mb.5","DOIUrl":"https://doi.org/10.1364/slada.1995.mb.5","url":null,"abstract":"We present a new physical approach to design of III-V middle-infrared diode lasers which can lead to increasing operating temperature of InAs-based lasers. Main pecularity of proposed method is using interface radiative recombination of spatially-separated carriers in type II broken-gap p-p heterojunctions (HJs). Lattice-machted nondoped and doped GaIn0.17As0.22Sb layers with high quality interface were grown on p-InAs (100). It was established that GaIn0.17As0.22Sb/InAs HJ is type II with broken-gap alignment.","PeriodicalId":365685,"journal":{"name":"Semiconductor Lasers Advanced Devices and Applications","volume":"2677 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121822245","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.1364/slada.1995.tub.5
J. Abshire, P. Millar, Xiaoli Sun
A laser ranging instrument is being developed to measure the spatial variations in the Earth's gravity field. It will range in space to a cube corner on a passive co-orbiting sub-satellite with a velocity accuracy of 20 to 50 um/sec by using AlGaAs lasers intensity modulated at 2 GHz.
{"title":"Semiconductor Laser-Based Ranging Instrument for Earth Gravity Measurements","authors":"J. Abshire, P. Millar, Xiaoli Sun","doi":"10.1364/slada.1995.tub.5","DOIUrl":"https://doi.org/10.1364/slada.1995.tub.5","url":null,"abstract":"A laser ranging instrument is being developed to measure the spatial\u0000 variations in the Earth's gravity field. It will range in space to a\u0000 cube corner on a passive co-orbiting sub-satellite with a velocity\u0000 accuracy of 20 to 50 um/sec by using AlGaAs lasers intensity modulated\u0000 at 2 GHz.","PeriodicalId":365685,"journal":{"name":"Semiconductor Lasers Advanced Devices and Applications","volume":"121 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131440260","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.1364/slada.1995.pdp.3
Narasimha P.R. Bhadri, Sushma Gupta, R. Jain, D. Brinkmann, W. S. Fu, S. Swirhun
We describe the first report of the use of VCSELs for spectroscopic applications. Using a 760 nm VCSEL tuned to one of the weak A band transitions of oxygen, a minimum detectivity of 1600 ppm was obtained, in these preliminary experiments.
{"title":"Use of vertical cavity surface emitting lasers(VCSELs) for spectroscopic applications","authors":"Narasimha P.R. Bhadri, Sushma Gupta, R. Jain, D. Brinkmann, W. S. Fu, S. Swirhun","doi":"10.1364/slada.1995.pdp.3","DOIUrl":"https://doi.org/10.1364/slada.1995.pdp.3","url":null,"abstract":"We describe the first report of the use of VCSELs for spectroscopic applications. Using a 760 nm VCSEL tuned to one of the weak A band transitions of oxygen, a minimum detectivity of 1600 ppm was obtained, in these preliminary experiments.","PeriodicalId":365685,"journal":{"name":"Semiconductor Lasers Advanced Devices and Applications","volume":"97 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130597263","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.1364/slada.1995.tue.7
J. Leegwater
Theories of laser mode-locking were developed in the seventies for dye lasers. However, semiconductor lasers are characterized by quite different parameters and the approximations that can be justified for dye lasers break down for semiconductor lasers. In this paper we study the resulting pulse duration using the model introduced by New and Haus [1, 2] with both slow and fast absorbers. In the fast-and-slow-absorber model of Haus the electric field of the pulse after round-trip i is given by a i (t). While propagating through the cavity the pulse is modified by each of the elements of the cavity in some way.
{"title":"Theory of Sub-Picosecond Semiconductor Lasers","authors":"J. Leegwater","doi":"10.1364/slada.1995.tue.7","DOIUrl":"https://doi.org/10.1364/slada.1995.tue.7","url":null,"abstract":"Theories of laser mode-locking were developed in the seventies for dye lasers. However, semiconductor lasers are characterized by quite different parameters and the approximations that can be justified for dye lasers break down for semiconductor lasers. In this paper we study the resulting pulse duration using the model introduced by New and Haus [1, 2] with both slow and fast absorbers. In the fast-and-slow-absorber model of Haus the electric field of the pulse after round-trip i is given by a\u0000 i\u0000 (t). While propagating through the cavity the pulse is modified by each of the elements of the cavity in some way.","PeriodicalId":365685,"journal":{"name":"Semiconductor Lasers Advanced Devices and Applications","volume":"91 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121505398","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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