Richard Laming - Profile on Academia.edu (original) (raw)

Papers by Richard Laming

Simulation of 50GHz Transmission Over 50km of Standard Fibre using Mid-point Spectral Inversion for Dispersion Compensation

Nonlinear Guided-Wave Phenomena

Transmission of 6ps linear pulse pairs over 50km of standard fibre is demonstrated by employing m... more Transmission of 6ps linear pulse pairs over 50km of standard fibre is demonstrated by employing midpoint spectral-inversion (phase conjugation) of the data signal to compensate dispersion effects. Pulse broadening as low as 10% and faithful reconstruction of the pulse patterns is observed and confirms the applicability of this technique to bit-rates greater than 100 Gbits-1.

Dispersion Compensation Gratings

Bragg Gratings, Photosensitivity, and Poling in Glass Fibers and Waveguides: Applications and Fundamentals

Broadband Chirped fibre gratings allow the upgrade of the existing non-dispersion shifted fibre n... more Broadband Chirped fibre gratings allow the upgrade of the existing non-dispersion shifted fibre network to high data rate operation within the 1.55μm low-loss window. The design, fabrication, performance and application of these devices is covered.

Reseau de guide d'ondes

Reseau de guide d'ondes (AWG) (1) comprenant un substrat possedant un premier groupe de guide... more Reseau de guide d'ondes (AWG) (1) comprenant un substrat possedant un premier groupe de guide d'ondes (8) couple optiquement entre un premier et un deuxieme coupleur a plaque (3, 4) et un deuxieme groupe de guide d'ondes d'entree/sortie (10) couples optiquement par leurs premieres extremites a un cote entree/sortie (5) du deuxieme coupleur a plaque (4). Ces guides d'ondes d'entree/sortie se retrecissent au niveau de premieres parties d'extremite (13), de maniere a croitre en largeur vers le deuxieme coupleur a plaque, et la largeur (W) des premieres extremites des guides d'ondes d'entree/sortie varie a travers le deuxieme groupe (10), de maniere a augmenter l'uniformite d'au moins un parametre de performance, par exemple, echo magnetique contigu (AXT). Dans le mode de realisation decrit, la largeur (W) des extremites decroissantes du guide d'ondes augmente depuis un cote du groupe de guides d'ondes d'entree/sortie (10) jusqu&#3...

Equalisation of Spectral Non-Uniformities in Broad-Band Chirped Fibre Gratings

Bragg Gratings, Photosensitivity, and Poling in Glass Fibers and Waveguides: Applications and Fundamentals

The use of chirped fibre Bragg gratings (FBGs) in a dispersion compensating role has been shown t... more The use of chirped fibre Bragg gratings (FBGs) in a dispersion compensating role has been shown to be a successful technology with great promise for future network upgrades [1,2]. A natural consequence of using FBGs in a negative dispersion sense is that although the structure is designed to phase-match forward- and backward-propagating LP01 modes, the phase-matching condition for coupling from the forward propagating fundamental mode to a higher order cladding-mode is also met for wavelengths just below that of the fundamental Bragg reflection. Because propagation in cladding-modes is extremely lossy there is a significant out-coupling of this shorter wavelength light. The chirped nature of FBGs designed for broad-band (> 5 nm) dispersion compensation means that this cladding-mode loss is integrated along the length of the grating with the result that the reflection spectrum has a slope extending from the short wavelength edge of the useable bandwidth. In a practical transmissio...

Design of apodised linearly-chirped fibre gratings for optical communications

The dispersion characteristics of hepatised linearly-chirped fibre gratings have been studied sys... more The dispersion characteristics of hepatised linearly-chirped fibre gratings have been studied systematically. It is shown that the hyperbolic tangent profile results in an overall superior performance, as it provides highly linearised time-delay characteristics with minimum reduction in the linear dispersion. To compensate for the linear dispersion of 100 km of standard telecom fibre over certain bandwidth (in nm), the required grating length is 19.24 cm/nm.

StRllgth. In this paper, we report on a novel method for reducing cladding-mode transmission loss... more StRllgth. In this paper, we report on a novel method for reducing cladding-mode transmission losses in standard FBG's. We show that short wavelength, transmission losses can be practically eliminated by damping the resonant excitation of the cladding modes. The damping is achieved by properly introducing a substantial propagation loss into the cladding modes. For maximum effect, the core mode should experience no extra propagation losses. By applying a thin lossy layer on the fibre cladding surface, a reduction of cladding-mode- losses of about 12dB was achieved. Transmission-loss suppression The cladding mode attenuation can be easily achieved by depositing a thin lossy layer on the cladding surface. Alternatively, the same effect can be accomplished by introducing one or more lossy layers into the fibre cladding during the fabrication process. The latter will result in a stronger cladding-modellossy-material overlap and, therefore, produce higher propagation losses.

StRllgth. In this paper, we report on a novel method for reducing cladding-mode transmission loss... more StRllgth. In this paper, we report on a novel method for reducing cladding-mode transmission losses in standard FBG's. We show that short wavelength, transmission losses can be practically eliminated by damping the resonant excitation of the cladding modes. The damping is achieved by properly introducing a substantial propagation loss into the cladding modes. For maximum effect, the core mode should experience no extra propagation losses. By applying a thin lossy layer on the fibre cladding surface, a reduction of cladding-mode- losses of about 12dB was achieved. Transmission-loss suppression The cladding mode attenuation can be easily achieved by depositing a thin lossy layer on the cladding surface. Alternatively, the same effect can be accomplished by introducing one or more lossy layers into the fibre cladding during the fabrication process. The latter will result in a stronger cladding-modellossy-material overlap and, therefore, produce higher propagation losses.

StRllgth. In this paper, we report on a novel method for reducing cladding-mode transmission loss... more StRllgth. In this paper, we report on a novel method for reducing cladding-mode transmission losses in standard FBG's. We show that short wavelength, transmission losses can be practically eliminated by damping the resonant excitation of the cladding modes. The damping is achieved by properly introducing a substantial propagation loss into the cladding modes. For maximum effect, the core mode should experience no extra propagation losses. By applying a thin lossy layer on the fibre cladding surface, a reduction of cladding-mode- losses of about 12dB was achieved. Transmission-loss suppression The cladding mode attenuation can be easily achieved by depositing a thin lossy layer on the cladding surface. Alternatively, the same effect can be accomplished by introducing one or more lossy layers into the fibre cladding during the fabrication process. The latter will result in a stronger cladding-modellossy-material overlap and, therefore, produce higher propagation losses.

Journal of Lightwave Technology, 1989

Journal of Lightwave Technology, 1998

Polarization independent (<0.01 dB) switching is achieved at 1.55 m in a strongly guiding, fused ... more Polarization independent (<0.01 dB) switching is achieved at 1.55 m in a strongly guiding, fused tapered fiber null coupler acoustooptic switch. An intermediate degree of fusion of the dissimilarly sized fibers is shown experimentally to have the form birefringence required to render the mode-splitting coupler polarization insensitive. The effect of the degree of fiber fusion on the acoustic wavelength of flexural waves is studied theoretically and experimentally, and precise control over the degree of fiber fusion is obtained for coupler waist cross-sectional dimensions as small as 6 m.

Journal of Lightwave Technology, 1990

IEEE Photonics Technology Letters, 1998

Long continuously chirped Moire fibre gratings are demonstrated. Clean, dual-channel operation wi... more Long continuously chirped Moire fibre gratings are demonstrated. Clean, dual-channel operation with dispersion equivalent to 100 km and 200 km of standard fibre is shown from gratings of lengths 35.1 cm and 1 m. The gratings show reflection and time delay characteristics of the same high quality as previously reported in single channel chirped gratings.

IEEE Photonics Technology Letters, 1998

Through a periodic sinc modulation of the refractive index-profile in fibre Bragg gratings we dem... more Through a periodic sinc modulation of the refractive index-profile in fibre Bragg gratings we demonstrate gratings with multiple equally spaced and identical wavelength channels. We show 10 cm long gratings with 4, 8 and 16 identical uniform wavelength channels separated by the ITU spacing of 100 GHz and a 22.5 cm long grating with 4 identical dispersion compensating channels with a 200 GHz separation designed to dispersion compensate 80 km data transmission through standard fibre at 1.55 µm.

Rayleigh scattering effect on the gain efficiency and noise of erbium-doped fiber amplifiers

IEEE Journal of Quantum Electronics, 1995

... Richard I. Laming was bom in Sheffield, England. on March 12, 1962. He received a first ... h... more ... Richard I. Laming was bom in Sheffield, England. on March 12, 1962. He received a first ... hundred publications. In 1988 and 1990, he was awarded the Pirelli and Senior Pirelli Research Fellowships respectively. In October ...

IEEE Journal of Quantum Electronics, 1998

The dispersion characteristics of apodized, linearly chirped fiber Bragg gratings and their poten... more The dispersion characteristics of apodized, linearly chirped fiber Bragg gratings and their potential as dispersion compensators have been studied systematically. It is shown that the positive hyperbolic-tangent profile results in an overall superior performance, as it provides highly linearized time-delay characteristics with minimum reduction in the linear dispersion. To compensate for the linear dispersion of 100 km of standard telecom fiber over certain bandwidth (in nanometers), the required grating length is 19.24 cm/nm.

3.988,697 10/1976 Cooley . 4,143,332 3/1979 Michan et al. ....................... 330/4.3 4.551,6... more 3.988,697 10/1976 Cooley . 4,143,332 3/1979 Michan et al. ....................... 330/4.3 4.551,684 1 1/1985 Bernhardt ............................ 330/4.3 4,794,346 2/1988 Miller ................................... 330/4.3 4,938,556 7/1990 Digannett et al. .................. 330/4.3 4,947,134 8/1990 Olsson .................................. 330/.43 4,955,025 9/1990 Mears et al. ............................ 372/6 5,067,789 1 1/1991 Hall et al. ............................. 385/27

Measurement of the intensity distribution in a fiber DFB laser is demonstrated by scanning a heat... more Measurement of the intensity distribution in a fiber DFB laser is demonstrated by scanning a heat source along the cavity and measuring the induced wavelength shift. Characterization of grating strength and the order of longitudinal mode operation is demonstrated, as well as location of the phaseshift position in an asymmetric phaseshifted DFB-laser with single-sided output.

Fiber Optic Sensors II, 1987

Fiber Laser Sources and Amplifiers II, 1991

Simulation of 50GHz Transmission Over 50km of Standard Fibre using Mid-point Spectral Inversion for Dispersion Compensation

Nonlinear Guided-Wave Phenomena

Transmission of 6ps linear pulse pairs over 50km of standard fibre is demonstrated by employing m... more Transmission of 6ps linear pulse pairs over 50km of standard fibre is demonstrated by employing midpoint spectral-inversion (phase conjugation) of the data signal to compensate dispersion effects. Pulse broadening as low as 10% and faithful reconstruction of the pulse patterns is observed and confirms the applicability of this technique to bit-rates greater than 100 Gbits-1.

Dispersion Compensation Gratings

Bragg Gratings, Photosensitivity, and Poling in Glass Fibers and Waveguides: Applications and Fundamentals

Broadband Chirped fibre gratings allow the upgrade of the existing non-dispersion shifted fibre n... more Broadband Chirped fibre gratings allow the upgrade of the existing non-dispersion shifted fibre network to high data rate operation within the 1.55μm low-loss window. The design, fabrication, performance and application of these devices is covered.

Reseau de guide d'ondes

Reseau de guide d'ondes (AWG) (1) comprenant un substrat possedant un premier groupe de guide... more Reseau de guide d'ondes (AWG) (1) comprenant un substrat possedant un premier groupe de guide d'ondes (8) couple optiquement entre un premier et un deuxieme coupleur a plaque (3, 4) et un deuxieme groupe de guide d'ondes d'entree/sortie (10) couples optiquement par leurs premieres extremites a un cote entree/sortie (5) du deuxieme coupleur a plaque (4). Ces guides d'ondes d'entree/sortie se retrecissent au niveau de premieres parties d'extremite (13), de maniere a croitre en largeur vers le deuxieme coupleur a plaque, et la largeur (W) des premieres extremites des guides d'ondes d'entree/sortie varie a travers le deuxieme groupe (10), de maniere a augmenter l'uniformite d'au moins un parametre de performance, par exemple, echo magnetique contigu (AXT). Dans le mode de realisation decrit, la largeur (W) des extremites decroissantes du guide d'ondes augmente depuis un cote du groupe de guides d'ondes d'entree/sortie (10) jusqu&#3...

Equalisation of Spectral Non-Uniformities in Broad-Band Chirped Fibre Gratings

Bragg Gratings, Photosensitivity, and Poling in Glass Fibers and Waveguides: Applications and Fundamentals

The use of chirped fibre Bragg gratings (FBGs) in a dispersion compensating role has been shown t... more The use of chirped fibre Bragg gratings (FBGs) in a dispersion compensating role has been shown to be a successful technology with great promise for future network upgrades [1,2]. A natural consequence of using FBGs in a negative dispersion sense is that although the structure is designed to phase-match forward- and backward-propagating LP01 modes, the phase-matching condition for coupling from the forward propagating fundamental mode to a higher order cladding-mode is also met for wavelengths just below that of the fundamental Bragg reflection. Because propagation in cladding-modes is extremely lossy there is a significant out-coupling of this shorter wavelength light. The chirped nature of FBGs designed for broad-band (> 5 nm) dispersion compensation means that this cladding-mode loss is integrated along the length of the grating with the result that the reflection spectrum has a slope extending from the short wavelength edge of the useable bandwidth. In a practical transmissio...

Design of apodised linearly-chirped fibre gratings for optical communications

The dispersion characteristics of hepatised linearly-chirped fibre gratings have been studied sys... more The dispersion characteristics of hepatised linearly-chirped fibre gratings have been studied systematically. It is shown that the hyperbolic tangent profile results in an overall superior performance, as it provides highly linearised time-delay characteristics with minimum reduction in the linear dispersion. To compensate for the linear dispersion of 100 km of standard telecom fibre over certain bandwidth (in nm), the required grating length is 19.24 cm/nm.

StRllgth. In this paper, we report on a novel method for reducing cladding-mode transmission loss... more StRllgth. In this paper, we report on a novel method for reducing cladding-mode transmission losses in standard FBG's. We show that short wavelength, transmission losses can be practically eliminated by damping the resonant excitation of the cladding modes. The damping is achieved by properly introducing a substantial propagation loss into the cladding modes. For maximum effect, the core mode should experience no extra propagation losses. By applying a thin lossy layer on the fibre cladding surface, a reduction of cladding-mode- losses of about 12dB was achieved. Transmission-loss suppression The cladding mode attenuation can be easily achieved by depositing a thin lossy layer on the cladding surface. Alternatively, the same effect can be accomplished by introducing one or more lossy layers into the fibre cladding during the fabrication process. The latter will result in a stronger cladding-modellossy-material overlap and, therefore, produce higher propagation losses.

StRllgth. In this paper, we report on a novel method for reducing cladding-mode transmission loss... more StRllgth. In this paper, we report on a novel method for reducing cladding-mode transmission losses in standard FBG's. We show that short wavelength, transmission losses can be practically eliminated by damping the resonant excitation of the cladding modes. The damping is achieved by properly introducing a substantial propagation loss into the cladding modes. For maximum effect, the core mode should experience no extra propagation losses. By applying a thin lossy layer on the fibre cladding surface, a reduction of cladding-mode- losses of about 12dB was achieved. Transmission-loss suppression The cladding mode attenuation can be easily achieved by depositing a thin lossy layer on the cladding surface. Alternatively, the same effect can be accomplished by introducing one or more lossy layers into the fibre cladding during the fabrication process. The latter will result in a stronger cladding-modellossy-material overlap and, therefore, produce higher propagation losses.

StRllgth. In this paper, we report on a novel method for reducing cladding-mode transmission loss... more StRllgth. In this paper, we report on a novel method for reducing cladding-mode transmission losses in standard FBG's. We show that short wavelength, transmission losses can be practically eliminated by damping the resonant excitation of the cladding modes. The damping is achieved by properly introducing a substantial propagation loss into the cladding modes. For maximum effect, the core mode should experience no extra propagation losses. By applying a thin lossy layer on the fibre cladding surface, a reduction of cladding-mode- losses of about 12dB was achieved. Transmission-loss suppression The cladding mode attenuation can be easily achieved by depositing a thin lossy layer on the cladding surface. Alternatively, the same effect can be accomplished by introducing one or more lossy layers into the fibre cladding during the fabrication process. The latter will result in a stronger cladding-modellossy-material overlap and, therefore, produce higher propagation losses.

Journal of Lightwave Technology, 1989

Journal of Lightwave Technology, 1998

Polarization independent (<0.01 dB) switching is achieved at 1.55 m in a strongly guiding, fused ... more Polarization independent (<0.01 dB) switching is achieved at 1.55 m in a strongly guiding, fused tapered fiber null coupler acoustooptic switch. An intermediate degree of fusion of the dissimilarly sized fibers is shown experimentally to have the form birefringence required to render the mode-splitting coupler polarization insensitive. The effect of the degree of fiber fusion on the acoustic wavelength of flexural waves is studied theoretically and experimentally, and precise control over the degree of fiber fusion is obtained for coupler waist cross-sectional dimensions as small as 6 m.

Journal of Lightwave Technology, 1990

IEEE Photonics Technology Letters, 1998

Long continuously chirped Moire fibre gratings are demonstrated. Clean, dual-channel operation wi... more Long continuously chirped Moire fibre gratings are demonstrated. Clean, dual-channel operation with dispersion equivalent to 100 km and 200 km of standard fibre is shown from gratings of lengths 35.1 cm and 1 m. The gratings show reflection and time delay characteristics of the same high quality as previously reported in single channel chirped gratings.

IEEE Photonics Technology Letters, 1998

Through a periodic sinc modulation of the refractive index-profile in fibre Bragg gratings we dem... more Through a periodic sinc modulation of the refractive index-profile in fibre Bragg gratings we demonstrate gratings with multiple equally spaced and identical wavelength channels. We show 10 cm long gratings with 4, 8 and 16 identical uniform wavelength channels separated by the ITU spacing of 100 GHz and a 22.5 cm long grating with 4 identical dispersion compensating channels with a 200 GHz separation designed to dispersion compensate 80 km data transmission through standard fibre at 1.55 µm.

Rayleigh scattering effect on the gain efficiency and noise of erbium-doped fiber amplifiers

IEEE Journal of Quantum Electronics, 1995

... Richard I. Laming was bom in Sheffield, England. on March 12, 1962. He received a first ... h... more ... Richard I. Laming was bom in Sheffield, England. on March 12, 1962. He received a first ... hundred publications. In 1988 and 1990, he was awarded the Pirelli and Senior Pirelli Research Fellowships respectively. In October ...

IEEE Journal of Quantum Electronics, 1998

The dispersion characteristics of apodized, linearly chirped fiber Bragg gratings and their poten... more The dispersion characteristics of apodized, linearly chirped fiber Bragg gratings and their potential as dispersion compensators have been studied systematically. It is shown that the positive hyperbolic-tangent profile results in an overall superior performance, as it provides highly linearized time-delay characteristics with minimum reduction in the linear dispersion. To compensate for the linear dispersion of 100 km of standard telecom fiber over certain bandwidth (in nanometers), the required grating length is 19.24 cm/nm.

3.988,697 10/1976 Cooley . 4,143,332 3/1979 Michan et al. ....................... 330/4.3 4.551,6... more 3.988,697 10/1976 Cooley . 4,143,332 3/1979 Michan et al. ....................... 330/4.3 4.551,684 1 1/1985 Bernhardt ............................ 330/4.3 4,794,346 2/1988 Miller ................................... 330/4.3 4,938,556 7/1990 Digannett et al. .................. 330/4.3 4,947,134 8/1990 Olsson .................................. 330/.43 4,955,025 9/1990 Mears et al. ............................ 372/6 5,067,789 1 1/1991 Hall et al. ............................. 385/27

Measurement of the intensity distribution in a fiber DFB laser is demonstrated by scanning a heat... more Measurement of the intensity distribution in a fiber DFB laser is demonstrated by scanning a heat source along the cavity and measuring the induced wavelength shift. Characterization of grating strength and the order of longitudinal mode operation is demonstrated, as well as location of the phaseshift position in an asymmetric phaseshifted DFB-laser with single-sided output.

Fiber Optic Sensors II, 1987

Fiber Laser Sources and Amplifiers II, 1991