Query: High-brightness pump sources using 2D VCSEL arrays: OPTO

Candidate papers:

abstract: Many applications require laser pump sources with high output power (tens to hundreds of Watts) in the smallest spot, with the smallest divergence. Such high brightness pump sources typically use edge emitting semiconductor lasers. However, it is also possible to use high power two dimensional vertical cavity surfaceemitting laser (VCSEL) arrays for this purpose. Using a single 976nm 2D VCSEL array chip in an external cavity configuration, combined with a matching micro lens array, we have demonstrated more than 30W output power from a 50mm/0.22NA fiber, corresponding to a brightness of 10MW/cm2.sr. This represents a substantial reduction in module complexity compared to edge emitter based modules with similar brightness. These novel high brightness pump sources exhibit some well known intrinsic VCSEL performance features such as wavelength stability and narrow spectrum. Power and brightness can be scaled up using polarization and spectral combining.
author_names: Jean-Francois P Seurin

Guoyang Xu

Qing Wang

Baiming Guo

Robert van Leeuwen

Alexander Miglo

Prachi Pradhan

James D Wynn

Viktor Khalfin

Chuni L Ghosh
title: High brightness pump sources using 2D VCSEL arrays
venue: OPTO
year: 2010

abstract: We review recent results on high power, high efficiency two dimensional vertical cavity surface emitting laser (VCSEL) arrays emitting around 980nm. Selectively oxidized, bottom emitting single VCSEL emitters with 51% power conversion efficiency were developed as the basic building block of these arrays. More than 230W of continuous wave (CW) power is demonstrated from a ~5mm x 5mm array chip. In quasi CW mode, smaller array chips exhibit 100W output power, corresponding to more than 3.5kW/cm2 of power density. High brightness arrays have also been developed for pumping fiber lasers, delivering a fiber output power of 40W. We show that many of the advantages of low power single VCSEL devices such as reliability, wavelength stability, low divergence circular beam, and low cost manufacturing are preserved for these high power arrays. VCSELs thus offer an attractive alternative to the dominant edge emitter technology for many applications requiring compact high power laser sources.
author_names: Jean-Francois P Seurin

Chuni L Ghosh

Viktor Khalfin

Aleksandr Miglo

Guoyang Xu

James D Wynn

Prachi Pradhan

L A D'asaro
title: High power high efficiency 2D VCSEL arrays
venue: SPIE OPTO
year: 2008

abstract: A face pumped Nd:YAG slab laser with high power output and temperature fluctuation adaptability is proposed and demonstrated for the first time. A two dimensional (2D) vertical cavity surface emitting laser (VCSEL) array at 808 nm with a low wavelength shift coefficient is used as the pump source with a total pump power of 1.38 kW. The array is cooled by a double layer vascularized macro channel heat sink for effective heat management. A 1064 nm maximum power of 437 W from the slab laser is obtained by optimizing the output coupling, and the power variation is only 4.9% over the temperature range from 16 degC to 34 degC. The results show that the high power slab laser pumped by VCSEL has an excellent performance in temperature tolerance and lower requirements for coolant, which is only water cooled by the macro channel heat sink and no need for deionized water; it also provides a solution for high power lasers used in the complicated environment. Furthermore, it is possible to scale the output power to ~kW level by further increasing the VCSEL pump power.
author_names: Peng-Cheng Di

Xue-peng Li

Rujia Wang

Xiao-Jun Wang

Da-Fu Cui

Qin-Jun Peng
title: High Power VCSEL Pumped Slab Laser With Temperature Fluctuation Adaptability
venue: IEEE Photonics Technology Letters
year: 2021

abstract: Vertical cavity surface emitting lasers (VCSELs) are attractive for many pumping and direct diode applications due to combined advantages in low cost, high reliability, narrow and thermally stable spectrum, high power scalability, and easy system integration, etc. We report our progress on electrically pumped, GaAs based, high power high brightness VCSELs and 2D arrays in the infrared wavelength range. At 976nm, over 5.5W peak CW output and 60% peak power conversion efficiency (PCE) were demonstrated with 225um oxide confined device. For 5x5mm arrays, peak PCE of 54% and peak power of >450W at 976nm, peak PCE of 46% and peak power of >110W at 808nm were achieved respectively under QCW conditions. External cavity configuration was used to improve the VCSEL brightness. Single mode output of 280mW and 37% PCE were realized from 80um device. For large 325um device, we obtained single mode (M2=1.1) CW output of 2.1W, corresponding to a brightness of 160MW/cm2*sr. Three major areas of applications using such VCSELs are discussed: 1. High brightness fiber output; 2. High power, high efficiency green lasers from 2nd harmonic generation. 3.34W green output with 21.2% PCE were achieved; 3. Pumping solid state lasers for high energy pulse generation. We have demonstrated Q switched pulses with 16.1mJ at 1064nm and 4.9mJ with 1W average power at 473nm.
author_names: Delai Zhou

Jean-Francois P Seurin

Guoyang Xu

Pu Zhao

Bing Xu

Tong Chen

Robert van Leeuwen

Joseph Matheussen

Qing Wang

Chuni L Ghosh
title: Progress on high power high brightness VCSELs and applications
venue: Photonics West Optoelectronic Materials and Devices
year: 2015

abstract: Summary form only given. We present the first reported results for linear arrays of /spl alpha/DFB lasers in the 915 nm and 1064 nm wavelength regimes with record high brightness values. We also present results for a 2D array of /spl alpha/DFB lasers at 915 nm with a record high brightness using a novel stacking architecture. To our knowledge, this is the highest reported brightness from a multi Watt semiconductor laser source and is over a factor of 5X higher than the accessible brightness of the highest power broad area bars reported to date. High brightness laser diode arrays are attractive sources for applications such as soldering, heat treatment, marking and pumping of solid state lasers.
author_names: Vince Wong

A Schoenfelder

S O'brien

Scott Demars

Robert J Lang
title: High brightness /spl alpha/DFB arrays at 915 nm and 1.06 /spl mu/m
year: 1999

abstract: Direct laser diodes can typically provide only a limited single mode power, while ultrahigh brightness is required for many of the market relevant applications. Thus, multistage power conversion schemes are applied, when the laser diodes are used just as a pumping source. In this paper we review the recent advances in ultra large output aperture edge emitting lasers based on the photonic band crystal (PBC) concept. The concept allows near and far field engineering robust to temperature and strain gradients and growth nonuniformities. High order modes are selectively filtered and the effective optical confinement of the fundamental mode can be dramatically enhanced. At first, we show that robust ultra narrow vertical beam divergence <5 deg. FWHM) can be achieved simultaneously with ultrahigh differential efficiency (80 85% and significant single mode power for several wavelengths of the key regions. A maximum single mode power of 1.4 W is achieved for 980 nm lasers. At second we extend the PBC concept towards the 2D photonic crystal. A significant field extension in the vertical direction allows a robust fabrication of the field coupled lateral multistripe PBC arrays with a total multistripe width of 0.2 mm. We also demonstrate that the concept of high order modes filtering works well also in the lateral direction. Finally, we address possible options for 3D managing of light towards wavelength stabilized laser operation by processing of the multistripe arrays along their lengths. The concept opens a way for 3D photonic crystal edge emitting lasers potentially allowing scalable single mode power increase to arbitrary high levels.
author_names: Nikita Yu Gordeev

Mikhail Maximov

Y M Shernyakov

Innokenty Novikov

Leonid Karachinsky

Vitaly A Shchukin

Th Kettler

Kristijan Posilovic

Nikolai N Ledentsov

Dieter Bimberg

R Duboc

Andre Sharon

D B Arbiv

Udi Ben-Ami
title: High power one two and three dimensional photonic crystal edge emitting laser diodes for ultra high brightness applications
venue: SPIE OPTO
year: 2008

abstract: High power laser diode arrays, which are made of stacks of individual or multistripe laser diodes, or in some cases vertical cavity surfaceemitting lasers (VCSELs) can put out watts to kilowatts of optical power for uses such as laser pumping, industrial heating, illumination, or as the input for fiber optic direct diode laser devices for materials processing or for medicine. Laser diodes typically have much higher electrical to optical (wall plug) efficiencies than other types of lasers; in fact, they are some of the most efficient light emitters known. The d i sadvantage of laser diode arrays is their rela t i v e l y low beam quality there are no sing le mode kilowatts level laser diode sources in our near future. However, there are many applications that do not require a single mode beam; in addition, laser manufacturers are constantly refining beamcombining techniques to produce ever brighter high power laser diode sources.
author_names: John Wallace
title: Diode arrays are compact high power light dynamos
year: 2015

abstract: High power 808nm semiconductor lasers are widely used for pumping neodymium doped yttrium aluminum garnet (Nd:YAG) crystal to produce high brightness lasing at 1064nm. In addition, there are growing interest to use such high power 808nm lasers in the field of automotive infra red (IR) illumination and medical aesthetic treatment. Vertical cavity surface emitting lasers (VCSELs) have emerged as a promising candidate and attracted increased interests for those applications, due to their combined advantages of high efficiency, low diverging circular beam, narrow emission spectrum with reduced temperature sensitivity, low cost manufacturability, simpler coupling optics, and increased reliability, especially at high temperatures. They can emit very high power with very high power density as they can be conveniently configured into large two dimensional arrays and modules of arrays. We report recent development on such high power, high efficiency 808nm VCSELs with industrial leading ~55% power conversion efficiency (PCE) Top emitting VCSELs were grown by MOCVD and processed into single devices and 2D arrays using selective wet oxidation process and substrate removal technique for efficient current confinement and heat removal. Peak PCE of 51% and peak power of 800W were achieved from 5x5mm array, corresponding to peak power density of ~4kW/cm2. Pumped with new generation of 2.3kW VCSEL module, Q switched laser pulse energy at 1064nm reached 46.9mJ, more than doubled from previously reported results.
author_names: Delai Zhou

Jean-Francois P Seurin

Guoyang Xu

Robert van Leeuwen

Alexander Miglo

Qing Wang

A R Kovsh

Chuni L Ghosh
title: Progress on high power 808nm VCSELs and applications
venue: OPTO
year: 2017

abstract: The context of this thesis falls in the wide applications of UV light sources such as sterilization and purification. Compared to the conventional UV sources (excimer lasers, Nd: YAG lasers or mercury lamps) the semiconductor devices have advantages in reliability, compactness, high efficiency and minimum environmental effects. On the material aspect, III nitrides (BAlGaInN) are promising candidates since they are chemically and physically stable with direct bandgaps covering from visible to DUV spectrum. On the structure aspect, vertical cavity surface emitting laser (VCSEL) is one of the most attractive configurations considering its low threshold, high efficiency, and the possibility for the integration of 2D arrays and the wafer level tests. It constitutes a multiple quantum well (MQW) active region sandwiched by a top and a bottom distributed Bragg reflector (DBR) However, no VCSELs can operate below 300 nm until now. The major challenges lie in the two main blocks: the emission efficiency of MQWs and the reflectivity of DBRs, which are limited by the quality of the substrates and epitaxial layers, optical polarization properties of the MQW emission, small refractive index contrast of the layers used for DBRs at short wavelengths, etc. The objective of this thesis is to address this need by studying metal organic vapor phase epitaxy (MOVPE) growth of BAlGaN materials, developing AlGaN MQWs with enhanced surface emission and exploring BAlN/AlGaN DBRs, for the future development of optically pumped VCSELs operating below 300 nm
author_names: Xianbo Li
title: BAlGaN based vertical cavity surface emitting lasers operating in deep UV region
venue: PHOTOPTICS 2016
year: 2016

abstract: The context of this thesis falls in the wide applications of UV light sources such as sterilization and purification. Compared to the conventional UV sources (excimer lasers, Nd: YAG lasers or mercury lamps) the semiconductor devices have advantages in reliability, compactness, high efficiency and minimum environmental effects. On the material aspect, III nitrides (BAlGaInN) are promising candidates since they are chemically and physically stable with direct bandgaps covering from visible to DUV spectrum. On the structure aspect, vertical cavity surface emitting laser (VCSEL) is one of the most attractive configurations considering its low threshold, high efficiency, and the possibility for the integration of 2D arrays and the wafer level tests. It constitutes a multiple quantum well (MQW) active region sandwiched by a top and a bottom distributed Bragg reflector (DBR) However, no VCSELs can operate below 300 nm until now. The major challenges lie in the two main blocks: the emission efficiency of MQWs and the reflectivity of DBRs, which are limited by the quality of the substrates and epitaxial layers, optical polarization properties of the MQW emission, small refractive index contrast of the layers used for DBRs at short wavelengths, etc. The objective of this thesis is to address this need by studying metal organic vapor phase epitaxy (MOVPE) growth of BAlGaN materials, developing AlGaN MQWs with enhanced surface emission and exploring BAlN/AlGaN DBRs, for the future development of optically pumped VCSELs operating below 300 nm
author_names: Xin Li
title: Lasers a cavite vertical emettant par la surface dans l'ultraviolet profond a base des materiaux BAlGaN
year: 2015