Prof. Xijia J. Gu Profile

Prof. Xijia J. Gu

Doctor at Toronto Metropolitan Univ

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Author

Publications (22)

Proceedings Article | 16 December 2022 Paper

Fabrication and spectral properties of two-dimensional fiber gratings based on LMA fiber

Zonglun Che, Jun Wang, Pan Xu, Xijia Gu, Jing Zhu, Lina Ma, Chunyan Cao

Proceedings Volume 12501, 125010P (2022) https://doi.org/10.1117/12.2656209

KEYWORDS: Structured optical fibers, Cladding, Fiber lasers, Optical fibers, Optical design, Excimer lasers, Ultraviolet radiation, Refractive index, Reflectivity, Reflection

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SPIE Journal Paper | 15 April 2020 Open Access

Doppler optical coherence tomography for energy seal evaluation and comparison to visual evaluation (Erratum)

Andrew Marques, Robnier Reyes, Christopher Pasarikovski, Chaoliang Chen, Joel Ramjist, Xijia Gu, Victor Yang

JBO, Vol. 25, Issue 04, 049801, (April 2020) https://doi.org/10.1117/12.10.1117/1.JBO.25.4.049801

KEYWORDS: Optical coherence tomography, Visualization, Doppler tomography, Biomedical engineering, Biomedical optics, Surgery, Medicine

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SPIE Journal Paper | 9 March 2020 Open Access

Doppler optical coherence tomography for energy seal evaluation and comparison to visual evaluation

Andrew Marques, Robnier Reyes, Christopher Pasarikovski, Chaoliang Chen, Joel Ramjist, Xijia Gu, Victor Yang

JBO, Vol. 25, Issue 03, 035003, (March 2020) https://doi.org/10.1117/12.10.1117/1.JBO.25.3.035003

KEYWORDS: Doppler tomography, Optical coherence tomography, Visualization, Laser systems engineering, Content addressable memory, Blood circulation, Laser irradiation, Ultrasonography, Surgery, Arteries

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Proceedings Article | 12 January 2018 Paper

Single-longitudinal mode distributed-feedback fiber laser with low-threshold and high-efficiency

Man Jiang, Pu Zhou, Xijia Gu

Proceedings Volume 10619, 106190F (2018) https://doi.org/10.1117/12.2296977

KEYWORDS: Fiber lasers, Fiber Bragg gratings, Structured optical fibers, Laser damage threshold, Glasses, Signal to noise ratio, Ions, Standards development, Doping, Excimer lasers

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Proceedings Article | 19 April 2017 Presentation

Coaxial cavity injected OCT and fiber laser ablation system for real-time monitoring of ablative processes part 2: toward all fiber design and dispersion control (Conference Presentation)

Jamil Jivraj, Jiaqi Zhou, Xijia Gu, Victor X. Yang

Proceedings Volume 10050, 100500C (2017) https://doi.org/10.1117/12.2253467

KEYWORDS: Mirrors, Tissue optics, Collimators, Lens design, Optical coherence tomography, Laser ablation, Fiber lasers, Laser systems engineering, Control systems, Medicine

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Proceedings Article | 19 April 2017 Presentation

The characterization of neural tissue ablation rate and corresponding heat affected zone of a 2 micron Tm3+ doped fiber laser (Conference Presentation)

Andrew Marques, Jamil Jivraj, Robnier Reyes, Joel Ramjist, Xijia Gu, Victor X. Yang

Proceedings Volume 10050, 100500D (2017) https://doi.org/10.1117/12.2256306

KEYWORDS: Laser ablation, Tissues, Laser tissue interaction, Fiber lasers, Tissue optics, Spine, Brain, Laser induced damage, Laser systems engineering, Bone

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Proceedings Article | 10 March 2015 Paper

Coaxial cavity injected OCT and fiber laser ablation system for real-time monitoring of ablative processes

Jamil Jivraj, Yize Huang, Ronnie Wong, Yi Lu, Barry Vuong, Joel Ramjist, Xijia Gu, Victor Yang

Proceedings Volume 9305, 930505 (2015) https://doi.org/10.1117/12.2080606

KEYWORDS: Optical coherence tomography, Fiber lasers, Laser ablation, Imaging systems, Linear filtering, Sensors, Laser systems engineering, Eye, Brain, Cameras

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Proceedings Article | 9 March 2015 Paper

Development of a low cost, 3-DOF desktop laser cutter using 3D printer hardware

Jamil Jivraj, Yize Huang, Ronnie Wong, Yi Lu, Barry Vuong, Joel Ramjist, Xijia Gu, Victor Yang

Proceedings Volume 9356, 93560N (2015) https://doi.org/10.1117/12.2080629

KEYWORDS: 3D printing, Head, Computer aided design, Laser cutting, Printing, Switches, Metals, 3D imaging standards, Fluctuations and noise, Fiber lasers

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Proceedings Article | 17 September 2013 Paper

Linearly polarized operation of a Yb3+-doped double-clad fiber laser

De-jun Feng, Wen-yu Huang, Pei-pei Zhang, Jun Zhou, Xi-jia Gu

Proceedings Volume 8904, 89041L (2013) https://doi.org/10.1117/12.2034953

KEYWORDS: Polarization, Fiber lasers, Phase modulation, Fiber Bragg gratings, Laser resonators, Reflectivity, Signal to noise ratio, Polarizers, Beam splitters, Polarization maintaining fibers

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Proceedings Article | 26 February 2013 Paper

Multi-wavelength S-band Tm:ZBLAN fiber lasers

B. Frison, A. Sarmani, L. Chen, X. Gu, M. Saad

Proceedings Volume 8601, 86011S (2013) https://doi.org/10.1117/12.2004655

KEYWORDS: Fiber lasers, Fiber Bragg gratings, ZBLAN, S band, Upconversion, Thulium, Wavelength division multiplexing, Silica, Fiber amplifiers, Spectrum analysis

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Tm³⁺-doped fluoride (ZBLAN) fibers offer amplification and lasing in a wide variety of wavelength ranges, including 810 nm, 1480 nm, 1900 nm, and 2300 nm.¹ Amplification and lasing around 1480 nm through the ³H₄→³F₄ transition is of interest for extending the capacity of WDM transmission systems, as well as developing sources for pumping erbium-doped fiber and fiber Raman amplifiers. The ³H₄→³F₄ transition, however, poses a challenge due to its self terminating nature. As such, the ³F₄ level can be depleted either by colasing at 1900 nm² or by using upconversion pumping at 1064 nm. High-power 1480 nm Tm³⁺:ZBLAN fiber lasers with upconversion pumping at 1064 nm have been demonstrated.^3-6 Recent research has focused on improving further the power conversion efficiency as well as the development of monolithic fiber lasers, e.g., by incorporating fiber Bragg gratings (FBGs) directly within the Tm³⁺: ZBLAN fiber gain medium. Dual-wavelength and multi-wavelength sources can have many applications in instrumentation (e.g., component testing), LIDAR systems, and fiber optics sensing. There have been several reports of dual-wavelength Tm³⁺-doped fiber lasers. For example, Androz et al. demonstrated operation at 785 nm and 810 nm, corresponding to the ¹G₄→³H₅ and ³H₄→³H₆ transitions, respectively, with a Tm³⁺:ZBLAN fiber gain medium.⁷ Wang et al. obtained dual-wavelength lasing around 2 μm with a tunable wavelength spacing from 1 nm – 40 nm in a Tm³⁺:silica fiber laser.⁸ We realized oscillation at 805 nm and 810 nm through the ³H₄→³H₆ transition in a Tm³⁺:ZBLAN fiber laser; we also reported wavelength switching capability as well as bistable operation in both single cavity and cascaded cavity configurations.⁹ In this paper, we extend our work further and report a dual-wavelength Tm³⁺:ZBLAN fiber laser operating in the S-band. Wavelength spacings of 11 nm and as narrow as 0.6 nm are achieved in a linear cascaded cavity configuration with bidirectional upconversion pumping at 1064 nm.

Proceedings Article | 5 December 2011 Paper

Highly polarized Yb-doped fiber laser based on a polarization-maintaining fiber Sagnac loop mirror and its power amplification

L. Zhang, J. H. Wang, X. J. Gu, Y. Feng

Proceedings Volume 8198, 81980M (2011) https://doi.org/10.1117/12.904460

KEYWORDS: Fiber lasers, Polarization, Mirrors, Phase modulation, Optical amplifiers, Fiber Bragg gratings, Reflectivity, Fiber amplifiers, Polarization maintaining fibers, Semiconductor lasers

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Proceedings Article | 19 August 2011 Paper

Preparation, package, and high-power fiber laser experiment of large mode-area fiber grating

Yuan-yuan Fan, Jun Zhou, Bing He, Ji-tuo Zheng, Hou-kang Liu, Xi-jia Gu, Qi-hong Lou

Proceedings Volume 8192, 81922C (2011) https://doi.org/10.1117/12.900574

KEYWORDS: Fiber Bragg gratings, Fiber lasers, High power fiber lasers, Reflectivity, Laser resonators, Mirrors, Cladding, Metals, High power lasers, Output couplers

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Proceedings Article | 17 February 2010 Paper

Hybrid Fourier domain modelocked laser utilizing a fiber optical parametric amplifier and an erbium doped fiber amplifier

Kyle H. Cheng, Beau Standish, Victor X. Yang, K. K. Cheung, Xijia Gu, Edmund Lam, K. K. Wong

Proceedings Volume 7580, 75802Q (2010) https://doi.org/10.1117/12.842720

KEYWORDS: Optical amplifiers, Fiber amplifiers, Optical filters, Fiber lasers, Optical coherence tomography, Electronic filtering, Erbium lasers, Image resolution, Single mode fibers, Fiber optics

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Proceedings Article | 17 February 2010 Paper

Cascaded Raman fiber laser in Fourier domain mode lock operation

Barry Vuong, Mark Harduar, Kyle H. Cheng, Xijia Gu, Lawrence Chen, Beau Standish, Victor X. Yang

Proceedings Volume 7580, 75802R (2010) https://doi.org/10.1117/12.842769

KEYWORDS: Raman spectroscopy, Fiber lasers, Fiber Bragg gratings, Quantum cascade lasers, Optical filters, Mirrors, Optical coherence tomography, Laser sources, Ytterbium, Optical testing

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Proceedings Article | 17 February 2010 Paper

Dual core ytterbium doped fiber ring laser in Fourier domain mode locked operation for swept-source optical coherence tomography

Mark Harduar, Adrian Mariampillai, Barry Vuong, Kyle H. Cheng, Lawrence Chen, Xijia Gu, Beau Standish, Victor X. Yang

Proceedings Volume 7580, 75802S (2010) https://doi.org/10.1117/12.842825

KEYWORDS: Ytterbium, Optical coherence tomography, Fiber lasers, Optical filters, Fiber amplifiers, Mode locking, Optical amplifiers, Laser sources, Electronic filtering, Absorption

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Proceedings Article | 11 August 2008 Paper

All-fiber laser beam shaping at 1.0 μm wavelength region in a single-mode fiber

Xijia Gu, Waleed Mohammed, Li Qian, Peter W. E. Smith

Proceedings Volume 7099, 70990L (2008) https://doi.org/10.1117/12.804764

KEYWORDS: Cladding, Beam shaping, Single mode fibers, Fiber lasers, High power fiber lasers, Laser applications, Laser therapeutics, Near field optics, Computer engineering, Medical laser equipment

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Proceedings Article | 14 October 2005 Paper

Versatile optical pulse shaping using a linearly chirped fibre Bragg grating and an amplitude mask

S. Neata, A. Wong, L. Qian, X. Gu, P. W. E. Smith

Proceedings Volume 5970, 59702H (2005) https://doi.org/10.1117/12.628725

KEYWORDS: Fiber Bragg gratings, Apodization, Pulse shaping, Algorithm development, Switching, Picosecond phenomena, Optical pulse shaping, Ultrafast phenomena, Optimization (mathematics), Modulation

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Optical pulse shaping finds many important applications in the area of ultrafast photonics. For example, in ultrafast all-optical switching, temporal shaping of the control pulses can be used to create a wide flat-top switching window with sharp rise and fall times. Such switching windows are more jitter-tolerant than simple Gaussian windows, and can therefore achieve a lower bit-error rate. Previously reported pulse shaping methods using linearly chirped Fibre Bragg Gratings (FBGs) take advantage of the direct correspondence between the spatial distribution of the grating periods and the temporal distribution of the spectral contents of the grating impulse response (space-to-frequency-to-time mapping). However, they have two major drawbacks: first, they are only valid for high-dispersion gratings, and therefore are unsuitable for producing short pulses; second, due to the inherent impulse response assumption, the power conversion efficiency is very low since the grating bandwidth needs to be much smaller than that of the input pulse. The numerical conversion efficiency demonstrated for this method is about a few percent. We report a versatile technique for temporal pulse shaping using a simple linearly chirped FBG and an amplitude mask. Unlike previous pulse shaping methods, ours is also applicable for low-dispersion gratings with bandwidths comparable to that of the input pulse (i.e., taking into account of finite input pulse duration). The chirped grating is used to stretch the incoming pulses to the desirable temporal width, while the amplitude mask modifies the shape of the pulses. We developed a novel optimization algorithm to obtain an amplitude mask that significantly increases the conversion efficiency. Pulse shaping using linearly chirped FBGs in the low dispersion regime is simulated using two methods. For weak gratings, the direct relationship between the spatial grating profile and the grating impulse response was used in tandem with a forward-correction deconvolution algorithm to solve for the optimum amplitude mask. For strong gratings, an optimization algorithm based on the partial validity of space-time mapping, as well as the causal relationship between the reflected temporal response and the grating apodization profile was used to design the amplitude mask. We experimentally demonstrated the conversion of 1-ps transform-limited Gaussian pulses to 10-ps pulses with a target shape at a high conversion efficiency of ~20% (measured) using a 1.5-mm-long grating. The spectral width of the pulses is 3.5 nm, centered at 1.55μm. As the reflected pulse shape is controlled by the shape of the amplitude mask, our method can be easily adapted to produce any arbitrary temporal pulse shape by designing an appropriate amplitude mask. To our knowledge, this is the first demonstration of this technique of arbitrary pulse shaping using the combination of a linearly chirped fiber grating and an amplitude mask in the low-dispersion regime.

Proceedings Article | 5 October 2005 Paper

Transmission efficiency improvement in microwave fiber-optic link using sub-picometer optic bandpass filter

X. Gu, Y. He, H. Kosek, X. Fernando

Proceedings Volume 5971, 597123 (2005) https://doi.org/10.1117/12.628088

KEYWORDS: Optical filters, Microwave radiation, Electronic filtering, Bandpass filters, Modulation, Fiber Bragg gratings, Receivers, Fiber optics, Telecommunications, Radio optics

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Proceedings Article | 4 October 2005 Paper

Optical domain demultiplexing of subcarrier multiplexed cellular and wireless LAN radio signals

Xavier Fernando, Hatice Kosek, Yifeng He, Xijia Gu

Proceedings Volume 5971, 59711S (2005) https://doi.org/10.1117/12.628125

KEYWORDS: Optical filters, Fiber Bragg gratings, Multiplexing, Electronic filtering, Bandpass filters, Local area networks, Radio optics, Microwave radiation, Modulators, Particle filters

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Proceedings Article | 20 December 2004 Paper

Amplified piezoelectric actuator with fine linear resolution

W. Zu, Xi-Jia Gu

Proceedings Volume 5577, (2004) https://doi.org/10.1117/12.566423

KEYWORDS: Actuators, Tunable filters, Feedback loops, Fiber Bragg gratings, Optical filters, Motion controllers, Wavelength tuning, Calibration, Biomedical optics, Transformers

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Proceedings Article | 8 September 1999 Paper

Influence of doping Y2O3 and Nb2O5 on ZrO2 characteristics in ZrO2-SiO2-P2O5 semiconductive ceramic humidity sensors

Xuzhou Hu, Xiaochun Hu, Yu Yang, Xinghui Wu, Henry van Driel, Xijia Gu

Proceedings Volume 3862, (1999) https://doi.org/10.1117/12.361147

KEYWORDS: Humidity, Sensors, Phonons, Ceramics, Absorption, Semiconductors, Raman spectroscopy, Infrared radiation, Raman scattering, X-ray diffraction

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Proceedings Article | 15 July 1999 Paper

Advanced-laser processing of photonic and microelectronic components at Photonics Research Ontario

Peter Herman, Gregory Goodno, Xijia Gu, Jeff Kalbfleisch, John Long, Marc Lukacs, Robin Marjoribanks, R. J. Miller, Marc Nantel, Sola Ness, Anton Oettl

Proceedings Volume 3618, (1999) https://doi.org/10.1117/12.352687

KEYWORDS: Laser processing, Etching, Glasses, Laser ablation, Micromachining, Laser applications, Silica, Absorption, Waveguides, Semiconductor lasers

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Showing 5 of 22 publications

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