Long-wavelength vertical-cavity surface-emitting laser using an electro-optic index modulator with 10 nm tuning range (original) (raw)
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Applied Physics Letters, 2011
A tunable vertical-cavity surface-emitting laser (VCSEL) is fabricated where tunability is achieved with an intracavity layer of nematic liquid crystal and gain is provided by a semiconductor quantum well structure. The anisotropic liquid crystal layer enables a continuously tunable single-mode emission along the extraordinary axis of the layer. Polarization control is achieved when the layer thickness is such that the ordinary modes are out of the spectral gain region. Laser emission in the 1.5 µm telecom wavelength range is demonstrated under optical pumping, with a tuning range of more than 30 nm for an applied voltage of less than 3 V.
Design and Fabrication of a Tunable InP-based VCSEL using a Electro-Optic Index Modulator
2006 International Conference on Indium Phosphide and Related Materials Conference Proceedings, 2006
We present the first vertical surface emitting laser (VCSEL) operating at 1.55-µm comprising a electro-optic modulator inside its cavity. This material consists of nematic liquid crystal dispersed in a polymer material (nano-PDLC). This first VCSEL exhibits a 10 nm tuning range and an excellent side-mode suppression ratio higher than 20 dB over the whole spectral range. The device is formed by a conventional InP-based active region with an epitaxial and a dielectric Bragg mirror. The nano-PDLC layer length, close to 6 µm, is in agreement with a tunable laser emission without mode-hopping. Another decisive advantage, compared to mechanical solutions, is the tuning response time which is close to a few 10 µs to scan the full spectral range, making this device appropriate for some access network functions. This first version is optically pumped and requires 170 volts to obtain a 10 nm tunability.
Optics Express, 2005
In this paper, we present an InP-based micromechanically tunable VCSEL emitting in the 1.55µm wavelength region with a 26nm tuning range. The laser is based on a two-chip concept, allowing for a separate optimization of the curved top mirror and the amplifying component. Current confinement is achieved by a buried tunnel junction. The design of the microcavity ensures fundamental mode operation with a side mode suppression ratio exceeding 49dB even for large apertures. Simulations indicate that the tuning range is limited by coupled cavity effects and reveal important design criteria like an upper boundary regarding the device thickness.
Recent progress of vertical-cavity surface emitting lasers: wavelength engineering and new functions
Active and Passive Optical Components for WDM Communications IV, 2004
Vertical cavity surface emitting lasers (VCSELs) have been extensively developed and are now key devices in local area networks based on multi-mode optical fibers. Long wavelength VCSELs are currently attracting much interest for use in single-mode fiber metropolitan area and wide area networks. Also, parallel data links including board-to-board interconnections with low threshold VCSEL arrays are also under development. Low threshold single-mode VCSEL arrays will enable us to realize parallel optical interconnects with low power consumption. We have developed highly strained GaInAs/GaAs QW VCSELs emitting at 1.1-1.2 µm band. Excellent temperature characteristics have been realized. We present long wavelength GaInAs VCSELs on GaAs substrates, enabling uncooled operation for high speed data transmission in single-mode fibers. Also, we will discuss a possibility of isolator-free operations of single-mode VCSELs. In addition, we demonstrated a single-mode multiple-wavelength VCSEL array on a patterned GaAs substrate for the wavelength engineering of VCSELs. The maximum lasing span of arrays is over 190 nm. Densely integrated multi-wavelength arrays are presented. Tunable micromachined VCSELs are also attracting much interest for WDM networking, because micromachined tunable VCSELs enable wide continuous tuning. We proposed and demonstrated a micromachined tunable vertical cavity with a strain control layer, which gives us novel functions including temperature insensitive operation, thermal wavelength tuning, and so on. We also propose and demonstrate injection-locked VCSELs for all-optical signal processing. Some results on optical inverters, optical bistable devices and optical regenerators will be reported. Toward other applications including optical storages and sensing, we will describe metal nano-aperture VCSELs for near-field optics.
Continuously Tunable Long-Wavelength MEMS-VCSEL With Over 40-nm Tuning Range
IEEE Photonics Technology Letters, 2004
This letter presents for the first time an electrically pumped tunable vertical-cavity surface-emitting laser (VCSEL) with a record-breaking tuning range of 40 nm at long wavelengths. The VCSEL is based on a two-chip concept. The laser peak can be tuned continuously and without mode-hopping in a wavelength range above 1.55 m due to a microelectromechanical movable mirror membrane. The VCSEL is single mode all over the tuning range with a 32-dB sidemode suppression ratio. The laser emits a maximum output power of 100 W in continuous-wave operation at room temperature. Dynamic measurements of the tuning characteristics show that the 3-dB cutoff frequency for an electrothermal wavelength modulation is about 500 Hz and the 1-time constant of the step response is about 1 ms.
Long wavelength MEMS tunable VCSEL with InP-InAlGaAs bottom DBR
IEEE Photonics Technology Letters, 2000
In this letter, we present the first demonstration of a long wavelength-tunable vertical-cavity surface-emitting laser (VCSEL) using an InP-InAlGaAs distributed Bragg reflector (DBR). The use of such a DBR improves the thermal resistance of the VCSEL while keeping the growth process simple. The devices show operation to temperatures greater than 75 C, and single-mode devices emit powers as high as 0.9 mW at room temperature. The tuning range is as high as 17 nm.
Short-wavelength MEMS-tunable VCSELs
Optics Express, 2008
We present electrically-injected MEMS-tunable vertical-cavity surface-emitting lasers with emission wavelengths below 800 nm. Operation in this wavelength range, near the oxygen A-band from 760−780 nm, is attractive for absorption-based optical gas sensing. These fully-monolithic devices are based on an oxide-aperture AlGaAs epitaxial structure and incorporate a suspended dielectric Bragg mirror for wavelength tuning. By implementing electrostatic actuation, we demonstrate the potential for tuning rates up to 1 MHz, as well as a wide wavelength tuning range of 30 nm (767−737 nm).
Vertical-cavity surface-emitting laser with a liquid crystal external cavity
Optics Letters, 2014
A tuneable external cavity consisting of a thin layer of nematic liquid crystal (LC) and a dielectric reflector is placed on the top of a vertical-cavity surface-emitting laser (VCSEL). By changing the voltage across the LC layer, the optical path length of the external cavity can be tuned. As a result, the emitting properties of the LC-VCSEL, including polarization state and emission wavelength can be controlled by the voltage applied over the LC layer. Stable polarization switching with high contrast is obtained by voltage driving. This device can be integrated in applications which require electrically tuneable VCSEL emission.
Micro-Optics, VCSELs, and Photonic Interconnects II: Fabrication, Packaging, and Integration, 2006
We present a new approach to achieve tunability on a 1.55 µm vertical cavity surface emitting laser (VCSEL). Tunability is achieved thanks to an electro-optic index modulator. This electro-optic material consists in a n-PDLC phase layer introduced inside the VCSEL cavity. N-PDLC comprises nematic liquid crystal dispersed in a polymer material. This first VCSEL exhibits a 10 nm tuning range and an excellent side-mode suppression ratio higher than 20 dB over the whole spectral range. The device is formed by a conventional InP-based active region with an epitaxial and a dielectric Bragg mirror. The n-PDLC layer length, close to 6 µm, is in agreement with a tunable laser emission without mode-hopping. Another decisive advantage, compared to mechanical solutions, is the tuning response time which is close to a few 10 µs to scan the full spectral range, making this device appropriate for some access network functions. Voltage values are the main limiting factor, 170 Volts have been required to obtain 10 nm tunability, but material engineering is in progress to improve this point. We presented a first version of the device optically pumped, the next version will be electrically pumped as required for access network applications targeted here.
International Journal of Physical Sciences, 2013
In this paper, a micro electromechanical systems vertical-cavity surface-emitting laser (MEMS-VCSEL) with asymmetric double oxide aperture and highly strained GaInNAsSb quantum wells for widely tunable, single mode and high temperature operation has been investigated. The MEMS-VCSEL is based on an integrated two-chip concept which allows us to extend the single wavelength performance to a continuously tunable, selectively wavelength-addressable spectrum of 40 nm. It has a much larger tuning range as compared with previous works. We present a comprehensive model including electrostatic membrane equation coupled with thermal, spatial and temporal rate equations considering Shockley Read Hall (SRH), Auger and carrier diffusion effects. These coupled equations are solved numerically by finite difference method (FDM). Using the simulation results, we design a single mode, high power, high temperature and tunable VCSEL, which is suitable for C-band dense-wavelengthdivision-multiplexing (DWDM) optical communication systems.