CST Global Ltd

Glasgow, United Kingdom

CST Global Ltd

Glasgow, United Kingdom

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Hou L.,University of Glasgow | Eddie I.,CST Global Ltd. | Marsh J.H.,University of Glasgow
2016 Conference on Lasers and Electro-Optics, CLEO 2016 | Year: 2016

The monolithic integration of four 40 GHz multi-colored mode-locked lasers with a 4×1 MMI, four electroabsorption modulators and an SOA has been demonstrated. The shortest pulse widths are between 2.63 and 2.85 ps. © 2016 OSA.


Hou L.,University of Glasgow | Xu J.,Chinese Academy of Sciences | Eddie I.,CST Global Ltd. | Han L.,Chinese Academy of Sciences | And 2 more authors.
2016 Conference on Lasers and Electro-Optics, CLEO 2016 | Year: 2016

We report side-wall sampled grating and quantum well intermixing techniques to fabricate a full function 4-channel DWDM source with excellent wavelength precision (residuals <0.13 nm) and high yield. Output power was >10 mW. © 2016 OSA.


Hou L.,University of Glasgow | Haji M.,National Physical Laboratory United Kingdom | Eddie I.,CST Global Ltd. | Zhu H.,CAS Institute of Semiconductors | Marsh J.H.,University of Glasgow
Optics Letters | Year: 2015

We present a laterally coupled dual wavelength 1.56/1.57-μm AlGaInAs/InP DFB laser, which, by introducing two different grating periods on each sidewall, emits two longitudinal modes simultaneously within the same cavity at a frequency separation of 0.82 THz. The beating signal is stabilized by nonlinear four-wave mixing in an electroabsorption modulator (EAM), located within a monolithically integrated resonant cavity. A stable 0.82-THz beating signal was observed over a wide range of bias parameters in terms of drive currents and bias to the DFB and EAM sections. © 2015 Optical Society of America.


Dhirhe D.,University of Glasgow | Slight T.J.,CST Global Ltd | Holmes B.M.,University of Glasgow | Ironside C.N.,University of Glasgow
Optics Express | Year: 2013

We discuss the design, modelling, fabrication and characterisation of an integrated tuneable birefringent waveguide for quantum cascade lasers. We have fabricated quantum cascade lasers operating at wavelengths around 4450 nm that include polarisation mode converters and a differential phase shift section. We employed below laser threshold electroluminescence to investigate the single pass operation of the integrated device. We use a theory based on the electro-optic properties of birefringence in quantum cascade laser waveguides combined with a Jones matrix based description to gain an understanding of the electroluminescence results. With the quantum cascade lasers operating above threshold we demonstrated polarisation control of the output. © 2013 Optical Society of America.


Nshii C.C.,University of Glasgow | Ironside C.N.,University of Glasgow | Sorel M.,University of Glasgow | Slight T.J.,University of Glasgow | And 4 more authors.
Applied Physics Letters | Year: 2010

We report on the design, fabrication, and characterization of a unidirectional quantum cascade ring laser operating at a wavelength of around 3.4 μm at 200 K. A unidirectional operation is achieved by incorporating an "S-shaped" crossover waveguide in a manner that it couples light from the counterclockwise direction to the preferred clockwise direction. The ring laser unidirectionality is confirmed by measuring the counterpropagating wave suppression ratio (CWSR) as a function of injection current. At 1.5 times the threshold current, the CWSR is 9 that is 90% of the light is emitted in the favored (clockwise) direction. © 2010 American Institute of Physics.


Dhirhe D.,University of Glasgow | Slight T.J.,CST Global Ltd | Nshii C.C.,University of Strathclyde | Ironside C.N.,University of Glasgow
Semiconductor Science and Technology | Year: 2012

The design, fabrication and characterization of a monolithic double-ring quantum- cascade laser (DRQCL) are described. At a wavelength of 4.6m, we demonstrate tunable, single-mode operation of a DRQCL and use it as a source for spectroscopy of CO gas. © 2012 IOP Publishing Ltd.


Hou L.,University of Glasgow | Tan M.,University of Glasgow | Haji M.,University of Glasgow | Eddie I.,CST Global Ltd. | Marsh J.H.,University of Glasgow
IEEE Photonics Technology Letters | Year: 2013

We, for the first time, present electroabsorption modulator lasers based on side-wall gratings and the identical epitaxial layer scheme using very simple fabrication processes. The devices show stable single-mode operation with little mode-hopping and a side mode suppression ratio of more than 45 dB, which is maintained until the applied current exceeds 6 times that of the threshold value. The drive voltage required to obtain a 12-dB extinction ratio is-2V. The devices can be operated with a 3-dB bandwidth of 7 GHz allowing for error-free large signal modulation at 5 Gb/s with a dynamic extinction ratio of 11 dB. © 1989-2012 IEEE.


Hou L.,University of Glasgow | Haji M.,National Physical Laboratory United Kingdom | Eddie I.,CST Global Ltd. | Zhu H.,CAS Institute of Semiconductors | Marsh J.H.,University of Glasgow
CLEO: Science and Innovations, CLEO-SI 2015 | Year: 2015

We present a laterally-coupled AlGaInAs/InP DFB laser emitting two longitudinal modes simultaneously within the same cavity and integrated with EAM. A stable 0.82 THz beating signal was observed over a wide range of bias parameters. © OSA 2015.


Dhirhe D.,University of Glasgow | Slight T.J.,CST Global Ltd | Holmes B.M.,University of Glasgow | Hutchings D.C.,University of Glasgow | Ironside C.N.,University of Glasgow
Optics Express | Year: 2012

We discuss the design, fabrication and characterization of waveguide polarization mode converters for quantum cascade lasers operating at 4.6 μm. We have fabricated a quantum cascade laser with integrated polarization mode converter that emits light of 69% Transverse Electrical (TE) polarization from one facet and 100% Transverse Magnetic (TM) polarization from the other facet. © 2012 Optical Society of America.


Cantu H.I.,CST Global Ltd. | Cantu H.I.,University of Glasgow | McKee A.,CST Global Ltd. | Eddie I.,CST Global Ltd. | Kelly A.E.,University of Glasgow
IEEE Journal of Quantum Electronics | Year: 2014

A demonstration of the effect of tuning components on a directly modulated distributed feedback laser (DFB) high-frequency performance is shown in this paper. A network based on three inductors and a microstrip line is used to impedance match the parasitic reactance of a laser diode within a tuning bandwidth. The matching and transmission performance of the laser under these conditions is compared with a radio frequency network simulation that include the intrinsic model of the DFB laser with its internal parasitic reactance, and the added external microstrip components. © 1965-2012 IEEE.

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