Andrey Umnikov
University of Southampton
Network
Latest external collaboration on country level. Dive into details by clicking on the dots.
Publication
Featured researches published by Andrey Umnikov.
Optics Letters | 2016
Naresh Kumar Thipparapu; Andrey Umnikov; Pranabesh Barua; J.K. Sahu
Bismuth (Bi)-doped phosphosilicate fibers have been fabricated by the modified chemical vapor deposition (MCVD)-solution doping technique under different process conditions. The influence of fabrication conditions on unsaturable loss in fibers has been investigated. Pump wavelength dependent Bi gain has been studied to obtain a flat gain over a wide bandwidth. A diode pumped all-fiber Bi-doped amplifier with a flat gain of 25±1 dB from 1320-1360 nm (40 nm) has been demonstrated for -10 dBm of input signal power with a noise figure (NF) ranging from 4-6 dB. Moreover, a small signal gain of 29 dB and a NF of 4.5 dB at 1340 nm has been achieved for an input signal power of -30 dBm.
Optics Letters | 2015
Naresh Kumar Thipparapu; Saurabh Jain; Andrey Umnikov; Pranabesh Barua; J.K. Sahu
Bismuth-doped aluminosilicate fiber has been fabricated by the MCVD-solution doping method and characterized for its unsaturable loss and gain. The amplifier performance has been compared for a novel pumping wavelength of 1120 nm with the conventional pumping wavelength region of 1047 nm. Unsaturable loss was 65% and 35% at 1047 and 1120 nm, pump wavelengths, respectively. A maximum gain of about 8 dB at 1180 nm for a fiber length of 100 m was observed with 1120 nm pumping. Gain enhancement of 70% was achieved with the 1120 nm pump as compared to the 1047 nm pump. A further 3.5 dB gain was obtained on simultaneous pumping at 1047 and 1120 nm.
european quantum electronics conference | 2017
Naresh Kumar Thipparapu; C. Guo; Andrey Umnikov; Pranabesh Barua; Austin Taranta; Shaif-ul Alam; J.K. Sahu
Bismuth (Bi)-doped fiber (BDF) lasers and amplifiers have been demonstrated in different glass hosts (i.e., aluminosilicate, phosphosilicate and germanosilicate) covering the 1150–1800nm wavelength region [1-3]. Pulsed Bi-doped fiber lasers (BDFLs) are of great interest owing to their potential applications in medicine, material processing and optical fiber communications. The first Bi-doped pulsed fiber laser was demonstrated in 2007 with 50ps pulses at 1161nm in a Bi-doped silicate fiber using SESAM as a saturable absorber (SA) [4]. A number of studies have since reported on BDFLs [3-6], however, the pulse dynamics in BDFs have not been fully understood due to the unsaturable loss and excited state absorption present in these fibers [7]. In this paper, we present an all fiber self-mode-locked BDFL operating at 1340nm with a minimum pulse width of 1.5ns, the first demonstration of its kind.
Archive | 2017
Naresh Kumar Thipparapu; Chunyun Guo; Pranabesh Barua; Andrey Umnikov; Austin Taranta; J.K. Sahu
Dataset supporting: Thipparapu, N. K., Guo, C., Barua, P., Umnikov, A., Taranta, A., & Sahu, J. (2017). Bismuth-doped all-fiber mode-locked laser operating at 1340 nm. Optics Letters, 42(24).
Archive | 2017
Naresh Kumar Thipparapu; Guo Chunyun; Andrey Umnikov; Pranabesh Barua; Austin Taranta; Shaif-ul Alam; J.K. Sahu
Bismuth (Bi)-doped fiber (BDF) lasers and amplifiers have been demonstrated in different glass hosts (i.e., aluminosilicate, phosphosilicate and germanosilicate) covering the 1150–1800nm wavelength region [1-3]. Pulsed Bi-doped fiber lasers (BDFLs) are of great interest owing to their potential applications in medicine, material processing and optical fiber communications. The first Bi-doped pulsed fiber laser was demonstrated in 2007 with 50ps pulses at 1161nm in a Bi-doped silicate fiber using SESAM as a saturable absorber (SA) [4]. A number of studies have since reported on BDFLs [3-6], however, the pulse dynamics in BDFs have not been fully understood due to the unsaturable loss and excited state absorption present in these fibers [7]. In this paper, we present an all fiber self-mode-locked BDFL operating at 1340nm with a minimum pulse width of 1.5ns, the first demonstration of its kind.
Archive | 2016
Naresh Kumar Thipparapu; Andrey Umnikov; Pranabesh Barua; J.K. Sahu
Bismuth (Bi) -doped phosphosilicate fibers have been fabricated by the modified chemical vapor deposition (MCVD) -solution doping technique under different process conditions. The influence of fabrication conditions on unsaturable loss in fibers has been investigated. Pump wavelength dependent Bi gain has been studied to obtain a flat gain over a wide bandwidth. A diode pumped all-fiber Bi-doped amplifier with a flat gain of 25 ± 1dB from 1320-1360nm (40nm) has been demonstrated for -10 dBm of input signal power with a noise figure (NF) ranging from 4–6 dB. Moreover, a small signal gain of 29 dB and a NF of 4.5dB at 1340 nm have been achieved for an input signal power of -30dBm.
Workshop on Specialty Optical Fibers and Their Applications (2015), paper WT1A.5 | 2015
Naresh Kumar Thipparapu; Andrey Umnikov; Saurabh Jain; Pranabesh Barua; J.K. Sahu
Bi-doped phosphosilicate fibers are fabricated by MCVD-solution doping technique under different oxidation conditions. Fibers are evaluated for unsaturable loss and laser performance. A 22mW all-fiber Bi-laser is demonstrated at 1360nm by LD pumping at 1267nm.
conference on lasers and electro optics | 2018
A. Halder; Di Lin; Andrey Umnikov; N.J. Ramirez-Martinez; M. Núñez-Velázquez; Pranabesh Barua; Shaif-ul Alam; J.K. Sahu
conference on lasers and electro optics | 2018
N.J. Ramirez-Martinez; M. Núñez-Velázquez; Andrey Umnikov; J.K. Sahu
Advanced Photonics 2018 (BGPP, IPR, NP, NOMA, Sensors, Networks, SPPCom, SOF) | 2018
N.J. Ramirez-Martinez; M. Núñez-Velázquez; Andrey Umnikov; J.K. Sahu