Kamal Dasgupta - Academia.edu (original) (raw)

Papers by Kamal Dasgupta

Research paper thumbnail of Comparison of thermal response of LPGs written in SMF-28 and B-Ge Co doped photosensitive fiber

In this paper, the effects of temperature on the spectral profiles of long period gratings (LPGs)... more In this paper, the effects of temperature on the spectral profiles of long period gratings (LPGs) fabricated in B-Ge co doped photosensitive fiber and standard single-mode fiber is investigated. The results obtained show that the temperature sensitivity of the LPG in the photosensitive fiber is considerably high compared with the SMF-28 fiber. It has also been observed that LPGs in a B-Ge co doped fiber have opposite sign of the temperature dependence compared with those in SMF-28 fiber.

Research paper thumbnail of Fiber Bragg grating accelerometer with enhanced sensitivity

Sensors and Actuators A: Physical, 2012

A cantilever based optical accelerometer with enhanced performance characteristics has been propo... more A cantilever based optical accelerometer with enhanced performance characteristics has been proposed. The sensitivity of the accelerometer has efficiently been enhanced by about twice as compared to the conventional design by tailoring the effective distance between the sensor axis to the neutral axis of the cantilever. The sensitivity enhancement has been done without affecting the characteristic resonant frequency of the

Research paper thumbnail of Erbium Doped Optical Fibres — Fabrication Technology

Journal of Optics, 2004

ABSTRACT Development of erbium doped optical preforms by two different techniques and subsequent ... more ABSTRACT Development of erbium doped optical preforms by two different techniques and subsequent drawing of these into fibres is described. The first technique involved deposition of porous silica-germanio soot layer by the modified chemical vapour deposition (MCVD) process followed by incorporation of erbium through the solution doping technique. Both forward and backward pass deposition techniques were investigated to determine their relative advantages/disadvantages. The second technique relied on coaling of inner surface of a silica lube with stable sols of erbium oxide coated silica nano-particles and subsequent processing through the MCVD process. The geometrical and optical characteristics of the fabricated preforms and fibres were extensively investigated in order to identify any specific problems and how to overcome/minimise these in order to optimise the process steps as well as the fabrication parameters. The performance of the fibres in terms of optical gain was measured under various pump and signal powers. Results of fabricated erbium doped fibres suitable for realising EDFAs with flat gain across the C-band (1530-1565 nm) are presented.

Research paper thumbnail of Radiation response behaviour of Al codoped germano-silicate SM fiber at high radiation dose

Optics Communications, 2009

Research paper thumbnail of <title>Effects of minor additives on the radiation response behavior of high silica glass single-mode fibers</title>

International Conference on Fiber Optics and Photonics: Selected Papers from Photonics India '98, 1999

ABSTRACT Using modified chemical vapor deposition (MCVD) process and the solution doping techniqu... more ABSTRACT Using modified chemical vapor deposition (MCVD) process and the solution doping technique germania doped single mode fibers with additives of Ce, Pb, Al, Y, Er and Nd in concentration of 1000 - 2000 ppm either singly or in combination were fabricated in long lengths. The fibers were exposed to gamma radiation from 60Co source at a dose rate of 300 - 400 rad/min for a total cumulative dose of 8 - 10 kilo rads at ambient temperature with on-line recording of the induced loss at 1300 nm. It was observed that the presence of minor quantities of dopants considerably influences the loss characteristics of the fibers recording highest radiation sensitivity in Nd doped ones while the co-doped fibers with Al+Y, Al+Pb and Al+Er have close range of sensitivity around 0.01 dB/Km.Rad.

Research paper thumbnail of Fabrication of Multimode Optical Fibres for Telecommunication

Transactions of the Indian Ceramic Society, 1988

ABSTRACT Experimental work on the preparation of high-silica glass preforms and drawing of multim... more ABSTRACT Experimental work on the preparation of high-silica glass preforms and drawing of multimode fibres therefrom have been presented. The details of the MCVD technique including salient features of dopant control programmes have been elaborated after describing briefly the basic equipment for preform fabrication; the fibre drawing technique has also been described in detail. The drawing parameters have been studied in terms of coating thickness variations. Transmission characteristics of fibres of twenty representative runs have been reported and discussed in order to assess their suitability for use in optical communication systems.

Research paper thumbnail of Fiber Bragg Grating Accelerometer for Non-stationary and Multi-frequency Signal Detection

12th International Conference on Fiber Optics and Photonics, 2014

Research paper thumbnail of Comparison between polyimide coated fiber grating and hydrogel coated long period grating for measuring sugar and salt concentration

2013 International Conference on Microwave and Photonics (ICMAP), 2013

Research paper thumbnail of Design optimization of fiber Bragg grating accelerometer for maximum sensitivity

Sensors and Actuators A: Physical, 2013

ABSTRACT Sensitivity of a cantilever-mass based fiber Bragg grating (FBG) accelerometer can effic... more ABSTRACT Sensitivity of a cantilever-mass based fiber Bragg grating (FBG) accelerometer can efficiently be tailored by altering the distance between the axis of the FBG sensor to the neutral axis of the cantilever. To accomplish that in general, a backing patch is used to mount the FBG on the cantilever. A numerical method to quantify the influence of the material constant (Young&#39;s modulus) of the backing patch and its thickness on the sensitivity is presented in this paper. It is explicitly shown that for a specific patch material there is an optimum thickness for which the sensitivity happens to be the maximum. A good agreement between simulation and experimental results is obtained. Finally, it is demonstrated that a sensitivity ∼1062 pm/g can be achieved, the enhancement almost by a factor of three as compared to that of the conventional cantilever-mass FBG accelerometer of similar bandwidth.

Research paper thumbnail of Radiation Resistant Optical Fiber for Visible Region

Passive Components and Fiber-Based Devices, 2011

Radiation resistance property of a series of optical preforms/fibers of different compositions in... more Radiation resistance property of a series of optical preforms/fibers of different compositions including those available commercially has been investigated to find out a suitable fiber in the UV-Visible wavelength range. The fibers drawn from commercial preforms exhibit feeble transmission in the UV zone prior to the radiation exposure and considerable darkening even with very low dose of radiation; although the preforms contain high OH in the core and it is claimed that higher OH content provides better transmission and radiation tolerance in the UV region. Radiation Induced Attenuation (RIA) dynamics for the wavelength range of 200 to 850 nm has been characterized ‘real-time’ under γ radiation. Dependence of RIA on the OH concentration in the core has been analyzed for wavelength band of 400–500 nm and at 630 nm. The generation of E' and NBOH color centers is responsible for the absorption at the above two wavelength bands respectively and is strongly influenced by the fiber composition. The effect of dose rate up to the accumulated dose of 1MRad has been studied. This systematic study led to the fabrication of a fiber with better radiation resistance characteristics in the wavelength range of 400–700 nm with out any radiation induced absorption peak at 630 nm.

Research paper thumbnail of Investigation on packages of fiber Bragg grating for use as embeddable strain sensor in concrete structure

Sensors and Actuators A: Physical, 2010

... b Experimental Mechanics Laboratory, Structural Engineering Research Centre, Council of Scien... more ... b Experimental Mechanics Laboratory, Structural Engineering Research Centre, Council of Scientific and Industrial Research (CSIR), Chennai, India. Received 20 August 2009; revised 28 October 2009; accepted 28 October 2009. Available online 10 November 2009. Abstract. ...

Research paper thumbnail of Detection and analysis of paraffin oil adulteration in coconut oil using fiber optic long period grating sensor

Optik - International Journal for Light and Electron Optics, 2011

... c , Corresponding Author Contact Information , E-mail The Corresponding Author , J. Linesh a ... more ... c , Corresponding Author Contact Information , E-mail The Corresponding Author , J. Linesh a , MC Bobby a , P. Biswas b , S. Bandyopadhyay b , K. Dasgupta b and ... The author TML is thankful to the Sree Chitra Thirunal College of Engineering, Trivandrum for their sponsorship. ...

Research paper thumbnail of Investigation of the deposition of porous layers by the MCVD method for the preparation of rare-earth doped cores of optical fibres

Optics Communications, 2005

Investigation was carried out on core layer deposition by modified chemical vapour deposition (MC... more Investigation was carried out on core layer deposition by modified chemical vapour deposition (MCVD) process to fabricate rare earth (RE) doped preforms and fibres. The solution doping technique was adopted for incorporation of the RE and codopant such as Al2O3 into the core. The deposited cores composed of GeO2/P2O5/SiO2 glasses with GeO2 level in the range of 3–15mol% and P2O5

Research paper thumbnail of Investigation of the optical gain and noise figure for multi-channel amplification in EDFA under optimized pump condition

Optics Communications, 2007

Research paper thumbnail of Study of the fabrication parameters of large core Yb2O3 doped optical fibre through solution doping technique

Optics Communications, 2010

Double clad large core Yb2O3 doped fibres with core diameter up to 20μm have been fabricated by t... more Double clad large core Yb2O3 doped fibres with core diameter up to 20μm have been fabricated by the solution doping technique through deposition of multiple porous core layers. The process parameters have been optimized with respect to the uniform doping of Al2O3 and Yb2O3 within the large core preform through soaking of the deposited multiple porous layers of fixed SiO2–P2O5

Research paper thumbnail of Gamma ray radiation induced absorption in Ti doped single mode optical fibres at low dose levels

Research paper thumbnail of Study of gain flatness for multi-channel amplification in single stage EDFA for WDM applications

Optical and Quantum Electronics, 2007

... Study of gain flatness for multi-channel amplification in single stage EDFA for WDM applicati... more ... Study of gain flatness for multi-channel amplification in single stage EDFA for WDM applications Mrinmay Pal · Somnath Bandyopadhyay · Palas Biswas · Rimlee Debroy · MC Paul · Ranjan Sen · Kamal Dasgupta · SK Bhadra ...

Research paper thumbnail of Radiation response behavior of high phosphorous doped step-index multimode optical fibers under low dose gamma irradiation

Journal of Non-Crystalline Solids, 2009

Research paper thumbnail of Empirical Relations for Design of Linear Edge Filters Using Apodized Linearly Chirped Fiber Bragg Grating

Journal of Lightwave Technology, 2000

Research paper thumbnail of Response of Strongly Over-coupled Resonant Mode of a Long Period Grating to High Refractive Index Ambiance

Journal of Lightwave Technology, 2000

ABSTRACT Over-coupling of the resonant band of interest has been found to have significant influe... more ABSTRACT Over-coupling of the resonant band of interest has been found to have significant influence on the refractive index sensitivity of long period grating (LPG) for surrounding material having refractive index higher than the cladding material. In this paper we report, for the first time to the best of our knowledge, a quantitative analysis using the concept of radiation mode coupling that elaborates the influence of initial coupling strength on the response of LPG to high refractive index surrounding. The simulated results agree well with those obtained experimentally where it could be shown that that a suitably over-coupled resonant mode of LPG can have a sensitivity ∼724 dB/RIU in the range of the ambient refractive index which is slightly higher than the cladding where the conventional LPGs have almost no sensitivity.

Research paper thumbnail of Comparison of thermal response of LPGs written in SMF-28 and B-Ge Co doped photosensitive fiber

In this paper, the effects of temperature on the spectral profiles of long period gratings (LPGs)... more In this paper, the effects of temperature on the spectral profiles of long period gratings (LPGs) fabricated in B-Ge co doped photosensitive fiber and standard single-mode fiber is investigated. The results obtained show that the temperature sensitivity of the LPG in the photosensitive fiber is considerably high compared with the SMF-28 fiber. It has also been observed that LPGs in a B-Ge co doped fiber have opposite sign of the temperature dependence compared with those in SMF-28 fiber.

Research paper thumbnail of Fiber Bragg grating accelerometer with enhanced sensitivity

Sensors and Actuators A: Physical, 2012

A cantilever based optical accelerometer with enhanced performance characteristics has been propo... more A cantilever based optical accelerometer with enhanced performance characteristics has been proposed. The sensitivity of the accelerometer has efficiently been enhanced by about twice as compared to the conventional design by tailoring the effective distance between the sensor axis to the neutral axis of the cantilever. The sensitivity enhancement has been done without affecting the characteristic resonant frequency of the

Research paper thumbnail of Erbium Doped Optical Fibres — Fabrication Technology

Journal of Optics, 2004

ABSTRACT Development of erbium doped optical preforms by two different techniques and subsequent ... more ABSTRACT Development of erbium doped optical preforms by two different techniques and subsequent drawing of these into fibres is described. The first technique involved deposition of porous silica-germanio soot layer by the modified chemical vapour deposition (MCVD) process followed by incorporation of erbium through the solution doping technique. Both forward and backward pass deposition techniques were investigated to determine their relative advantages/disadvantages. The second technique relied on coaling of inner surface of a silica lube with stable sols of erbium oxide coated silica nano-particles and subsequent processing through the MCVD process. The geometrical and optical characteristics of the fabricated preforms and fibres were extensively investigated in order to identify any specific problems and how to overcome/minimise these in order to optimise the process steps as well as the fabrication parameters. The performance of the fibres in terms of optical gain was measured under various pump and signal powers. Results of fabricated erbium doped fibres suitable for realising EDFAs with flat gain across the C-band (1530-1565 nm) are presented.

Research paper thumbnail of Radiation response behaviour of Al codoped germano-silicate SM fiber at high radiation dose

Optics Communications, 2009

Research paper thumbnail of <title>Effects of minor additives on the radiation response behavior of high silica glass single-mode fibers</title>

International Conference on Fiber Optics and Photonics: Selected Papers from Photonics India '98, 1999

ABSTRACT Using modified chemical vapor deposition (MCVD) process and the solution doping techniqu... more ABSTRACT Using modified chemical vapor deposition (MCVD) process and the solution doping technique germania doped single mode fibers with additives of Ce, Pb, Al, Y, Er and Nd in concentration of 1000 - 2000 ppm either singly or in combination were fabricated in long lengths. The fibers were exposed to gamma radiation from 60Co source at a dose rate of 300 - 400 rad/min for a total cumulative dose of 8 - 10 kilo rads at ambient temperature with on-line recording of the induced loss at 1300 nm. It was observed that the presence of minor quantities of dopants considerably influences the loss characteristics of the fibers recording highest radiation sensitivity in Nd doped ones while the co-doped fibers with Al+Y, Al+Pb and Al+Er have close range of sensitivity around 0.01 dB/Km.Rad.

Research paper thumbnail of Fabrication of Multimode Optical Fibres for Telecommunication

Transactions of the Indian Ceramic Society, 1988

ABSTRACT Experimental work on the preparation of high-silica glass preforms and drawing of multim... more ABSTRACT Experimental work on the preparation of high-silica glass preforms and drawing of multimode fibres therefrom have been presented. The details of the MCVD technique including salient features of dopant control programmes have been elaborated after describing briefly the basic equipment for preform fabrication; the fibre drawing technique has also been described in detail. The drawing parameters have been studied in terms of coating thickness variations. Transmission characteristics of fibres of twenty representative runs have been reported and discussed in order to assess their suitability for use in optical communication systems.

Research paper thumbnail of Fiber Bragg Grating Accelerometer for Non-stationary and Multi-frequency Signal Detection

12th International Conference on Fiber Optics and Photonics, 2014

Research paper thumbnail of Comparison between polyimide coated fiber grating and hydrogel coated long period grating for measuring sugar and salt concentration

2013 International Conference on Microwave and Photonics (ICMAP), 2013

Research paper thumbnail of Design optimization of fiber Bragg grating accelerometer for maximum sensitivity

Sensors and Actuators A: Physical, 2013

ABSTRACT Sensitivity of a cantilever-mass based fiber Bragg grating (FBG) accelerometer can effic... more ABSTRACT Sensitivity of a cantilever-mass based fiber Bragg grating (FBG) accelerometer can efficiently be tailored by altering the distance between the axis of the FBG sensor to the neutral axis of the cantilever. To accomplish that in general, a backing patch is used to mount the FBG on the cantilever. A numerical method to quantify the influence of the material constant (Young&#39;s modulus) of the backing patch and its thickness on the sensitivity is presented in this paper. It is explicitly shown that for a specific patch material there is an optimum thickness for which the sensitivity happens to be the maximum. A good agreement between simulation and experimental results is obtained. Finally, it is demonstrated that a sensitivity ∼1062 pm/g can be achieved, the enhancement almost by a factor of three as compared to that of the conventional cantilever-mass FBG accelerometer of similar bandwidth.

Research paper thumbnail of Radiation Resistant Optical Fiber for Visible Region

Passive Components and Fiber-Based Devices, 2011

Radiation resistance property of a series of optical preforms/fibers of different compositions in... more Radiation resistance property of a series of optical preforms/fibers of different compositions including those available commercially has been investigated to find out a suitable fiber in the UV-Visible wavelength range. The fibers drawn from commercial preforms exhibit feeble transmission in the UV zone prior to the radiation exposure and considerable darkening even with very low dose of radiation; although the preforms contain high OH in the core and it is claimed that higher OH content provides better transmission and radiation tolerance in the UV region. Radiation Induced Attenuation (RIA) dynamics for the wavelength range of 200 to 850 nm has been characterized ‘real-time’ under γ radiation. Dependence of RIA on the OH concentration in the core has been analyzed for wavelength band of 400–500 nm and at 630 nm. The generation of E' and NBOH color centers is responsible for the absorption at the above two wavelength bands respectively and is strongly influenced by the fiber composition. The effect of dose rate up to the accumulated dose of 1MRad has been studied. This systematic study led to the fabrication of a fiber with better radiation resistance characteristics in the wavelength range of 400–700 nm with out any radiation induced absorption peak at 630 nm.

Research paper thumbnail of Investigation on packages of fiber Bragg grating for use as embeddable strain sensor in concrete structure

Sensors and Actuators A: Physical, 2010

... b Experimental Mechanics Laboratory, Structural Engineering Research Centre, Council of Scien... more ... b Experimental Mechanics Laboratory, Structural Engineering Research Centre, Council of Scientific and Industrial Research (CSIR), Chennai, India. Received 20 August 2009; revised 28 October 2009; accepted 28 October 2009. Available online 10 November 2009. Abstract. ...

Research paper thumbnail of Detection and analysis of paraffin oil adulteration in coconut oil using fiber optic long period grating sensor

Optik - International Journal for Light and Electron Optics, 2011

... c , Corresponding Author Contact Information , E-mail The Corresponding Author , J. Linesh a ... more ... c , Corresponding Author Contact Information , E-mail The Corresponding Author , J. Linesh a , MC Bobby a , P. Biswas b , S. Bandyopadhyay b , K. Dasgupta b and ... The author TML is thankful to the Sree Chitra Thirunal College of Engineering, Trivandrum for their sponsorship. ...

Research paper thumbnail of Investigation of the deposition of porous layers by the MCVD method for the preparation of rare-earth doped cores of optical fibres

Optics Communications, 2005

Investigation was carried out on core layer deposition by modified chemical vapour deposition (MC... more Investigation was carried out on core layer deposition by modified chemical vapour deposition (MCVD) process to fabricate rare earth (RE) doped preforms and fibres. The solution doping technique was adopted for incorporation of the RE and codopant such as Al2O3 into the core. The deposited cores composed of GeO2/P2O5/SiO2 glasses with GeO2 level in the range of 3–15mol% and P2O5

Research paper thumbnail of Investigation of the optical gain and noise figure for multi-channel amplification in EDFA under optimized pump condition

Optics Communications, 2007

Research paper thumbnail of Study of the fabrication parameters of large core Yb2O3 doped optical fibre through solution doping technique

Optics Communications, 2010

Double clad large core Yb2O3 doped fibres with core diameter up to 20μm have been fabricated by t... more Double clad large core Yb2O3 doped fibres with core diameter up to 20μm have been fabricated by the solution doping technique through deposition of multiple porous core layers. The process parameters have been optimized with respect to the uniform doping of Al2O3 and Yb2O3 within the large core preform through soaking of the deposited multiple porous layers of fixed SiO2–P2O5

Research paper thumbnail of Gamma ray radiation induced absorption in Ti doped single mode optical fibres at low dose levels

Research paper thumbnail of Study of gain flatness for multi-channel amplification in single stage EDFA for WDM applications

Optical and Quantum Electronics, 2007

... Study of gain flatness for multi-channel amplification in single stage EDFA for WDM applicati... more ... Study of gain flatness for multi-channel amplification in single stage EDFA for WDM applications Mrinmay Pal · Somnath Bandyopadhyay · Palas Biswas · Rimlee Debroy · MC Paul · Ranjan Sen · Kamal Dasgupta · SK Bhadra ...

Research paper thumbnail of Radiation response behavior of high phosphorous doped step-index multimode optical fibers under low dose gamma irradiation

Journal of Non-Crystalline Solids, 2009

Research paper thumbnail of Empirical Relations for Design of Linear Edge Filters Using Apodized Linearly Chirped Fiber Bragg Grating

Journal of Lightwave Technology, 2000

Research paper thumbnail of Response of Strongly Over-coupled Resonant Mode of a Long Period Grating to High Refractive Index Ambiance

Journal of Lightwave Technology, 2000

ABSTRACT Over-coupling of the resonant band of interest has been found to have significant influe... more ABSTRACT Over-coupling of the resonant band of interest has been found to have significant influence on the refractive index sensitivity of long period grating (LPG) for surrounding material having refractive index higher than the cladding material. In this paper we report, for the first time to the best of our knowledge, a quantitative analysis using the concept of radiation mode coupling that elaborates the influence of initial coupling strength on the response of LPG to high refractive index surrounding. The simulated results agree well with those obtained experimentally where it could be shown that that a suitably over-coupled resonant mode of LPG can have a sensitivity ∼724 dB/RIU in the range of the ambient refractive index which is slightly higher than the cladding where the conventional LPGs have almost no sensitivity.