Optical multi-stable operations of coupled lasers

S. Zhang

Research output: ThesisPhd Thesis 1 (Research TU/e / Graduation TU/e)Academic

Abstract

Optical memories are optical bi(multi-)stable systems whose states can be switched all optically. Acting as a fundamental building block for digital optical signal processing, they have received considerable attention. Many types of optical memories have been explored, which all have in common that they are optical storage elements with two states. Multi-stable optical logic building blocks are interesting for applications in telecommunication systems, since they have potential to process a large number of wavelength channels in parallel. In this thesis, we present two types of multi-stable operation of coupled lasers. The first one is based on coupled ring lasers, which share a single active element and a feedback arm. A single ring laser with feedback can be regarded as an oscillator, since the intensity of the lasing light in the lasing cavity is periodically oscillating. When two such oscillators are coupled together, sharing the same active element and the same feedback arm, they synchronize in a common oscillation frequency if their individual oscillation periodicities are close to each other; otherwise they show bistability between the two oscillators. Switching between different stable states can be realized by injecting external light, in this sense, the system act as an optical memory. Moreover, this concept can easily realize multi-state operation, since only one active element is required. An eight-state optical memory is demonstrated. The second type of multi-stable operation of coupled lasers is based on serially interconnected lasers using the principle of gain quenching. The light from the dominant laser suppresses its neighboring lasers through gain saturation, but still receives amplification by the active element of the suppressed lasers, compensating for coupling losses. This light passes through each of the successive lasers, simultaneously suppressing and being amplified. By this mechanism all the other lasers are suppressed. Only one of the lasers can lase at a time, thus the state of the optical memory is determined by the wavelength of the dominant laser, as same as the first type. A five-state optical memory based on this concept is experimentally demonstrated. Moreover, we use the optical memories as a fundamental logic unit to realize sophisticated optical logic. We present an optical shift register that consists of two serially connected optical memories driven by common clock pulses. The concept is demonstrated at an operation speed of 20 kHz, which is limited by the laser cavities implemented by 10 meter long fiber pigtailed components. Furthermore, we cascade the optical shift register and an optical XOR gate to realize an optical pseudorandom number generator based on optical memories.
LanguageEnglish
QualificationDoctor of Philosophy
Awarding Institution
  • Department of Electrical Engineering
Supervisors/Advisors
  • Khoe, Djan, Promotor
  • Lenstra, Daan, Promotor
  • Dorren, Harm, Copromotor
Award date5 Oct 2006
Place of PublicationEindhoven
Publisher
Print ISBNs90-386-1873-5
DOIs
StatePublished - 2006

Fingerprint

lasers
shift registers
oscillators
ring lasers
logic
lasing
arithmetic and logic units
oscillations
theses
laser cavities
clocks
optical communication
periodic variations
signal processing
quenching
saturation
cavities
fibers
pulses
wavelengths

Cite this

Zhang, S. (2006). Optical multi-stable operations of coupled lasers Eindhoven: Technische Universiteit Eindhoven DOI: 10.6100/IR613180
Zhang, S.. / Optical multi-stable operations of coupled lasers. Eindhoven : Technische Universiteit Eindhoven, 2006. 124 p.
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title = "Optical multi-stable operations of coupled lasers",
abstract = "Optical memories are optical bi(multi-)stable systems whose states can be switched all optically. Acting as a fundamental building block for digital optical signal processing, they have received considerable attention. Many types of optical memories have been explored, which all have in common that they are optical storage elements with two states. Multi-stable optical logic building blocks are interesting for applications in telecommunication systems, since they have potential to process a large number of wavelength channels in parallel. In this thesis, we present two types of multi-stable operation of coupled lasers. The first one is based on coupled ring lasers, which share a single active element and a feedback arm. A single ring laser with feedback can be regarded as an oscillator, since the intensity of the lasing light in the lasing cavity is periodically oscillating. When two such oscillators are coupled together, sharing the same active element and the same feedback arm, they synchronize in a common oscillation frequency if their individual oscillation periodicities are close to each other; otherwise they show bistability between the two oscillators. Switching between different stable states can be realized by injecting external light, in this sense, the system act as an optical memory. Moreover, this concept can easily realize multi-state operation, since only one active element is required. An eight-state optical memory is demonstrated. The second type of multi-stable operation of coupled lasers is based on serially interconnected lasers using the principle of gain quenching. The light from the dominant laser suppresses its neighboring lasers through gain saturation, but still receives amplification by the active element of the suppressed lasers, compensating for coupling losses. This light passes through each of the successive lasers, simultaneously suppressing and being amplified. By this mechanism all the other lasers are suppressed. Only one of the lasers can lase at a time, thus the state of the optical memory is determined by the wavelength of the dominant laser, as same as the first type. A five-state optical memory based on this concept is experimentally demonstrated. Moreover, we use the optical memories as a fundamental logic unit to realize sophisticated optical logic. We present an optical shift register that consists of two serially connected optical memories driven by common clock pulses. The concept is demonstrated at an operation speed of 20 kHz, which is limited by the laser cavities implemented by 10 meter long fiber pigtailed components. Furthermore, we cascade the optical shift register and an optical XOR gate to realize an optical pseudorandom number generator based on optical memories.",
author = "S. Zhang",
year = "2006",
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publisher = "Technische Universiteit Eindhoven",
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Zhang, S 2006, 'Optical multi-stable operations of coupled lasers', Doctor of Philosophy, Department of Electrical Engineering, Eindhoven. DOI: 10.6100/IR613180

Optical multi-stable operations of coupled lasers. / Zhang, S.

Eindhoven : Technische Universiteit Eindhoven, 2006. 124 p.

Research output: ThesisPhd Thesis 1 (Research TU/e / Graduation TU/e)Academic

TY - THES

T1 - Optical multi-stable operations of coupled lasers

AU - Zhang,S.

PY - 2006

Y1 - 2006

N2 - Optical memories are optical bi(multi-)stable systems whose states can be switched all optically. Acting as a fundamental building block for digital optical signal processing, they have received considerable attention. Many types of optical memories have been explored, which all have in common that they are optical storage elements with two states. Multi-stable optical logic building blocks are interesting for applications in telecommunication systems, since they have potential to process a large number of wavelength channels in parallel. In this thesis, we present two types of multi-stable operation of coupled lasers. The first one is based on coupled ring lasers, which share a single active element and a feedback arm. A single ring laser with feedback can be regarded as an oscillator, since the intensity of the lasing light in the lasing cavity is periodically oscillating. When two such oscillators are coupled together, sharing the same active element and the same feedback arm, they synchronize in a common oscillation frequency if their individual oscillation periodicities are close to each other; otherwise they show bistability between the two oscillators. Switching between different stable states can be realized by injecting external light, in this sense, the system act as an optical memory. Moreover, this concept can easily realize multi-state operation, since only one active element is required. An eight-state optical memory is demonstrated. The second type of multi-stable operation of coupled lasers is based on serially interconnected lasers using the principle of gain quenching. The light from the dominant laser suppresses its neighboring lasers through gain saturation, but still receives amplification by the active element of the suppressed lasers, compensating for coupling losses. This light passes through each of the successive lasers, simultaneously suppressing and being amplified. By this mechanism all the other lasers are suppressed. Only one of the lasers can lase at a time, thus the state of the optical memory is determined by the wavelength of the dominant laser, as same as the first type. A five-state optical memory based on this concept is experimentally demonstrated. Moreover, we use the optical memories as a fundamental logic unit to realize sophisticated optical logic. We present an optical shift register that consists of two serially connected optical memories driven by common clock pulses. The concept is demonstrated at an operation speed of 20 kHz, which is limited by the laser cavities implemented by 10 meter long fiber pigtailed components. Furthermore, we cascade the optical shift register and an optical XOR gate to realize an optical pseudorandom number generator based on optical memories.

AB - Optical memories are optical bi(multi-)stable systems whose states can be switched all optically. Acting as a fundamental building block for digital optical signal processing, they have received considerable attention. Many types of optical memories have been explored, which all have in common that they are optical storage elements with two states. Multi-stable optical logic building blocks are interesting for applications in telecommunication systems, since they have potential to process a large number of wavelength channels in parallel. In this thesis, we present two types of multi-stable operation of coupled lasers. The first one is based on coupled ring lasers, which share a single active element and a feedback arm. A single ring laser with feedback can be regarded as an oscillator, since the intensity of the lasing light in the lasing cavity is periodically oscillating. When two such oscillators are coupled together, sharing the same active element and the same feedback arm, they synchronize in a common oscillation frequency if their individual oscillation periodicities are close to each other; otherwise they show bistability between the two oscillators. Switching between different stable states can be realized by injecting external light, in this sense, the system act as an optical memory. Moreover, this concept can easily realize multi-state operation, since only one active element is required. An eight-state optical memory is demonstrated. The second type of multi-stable operation of coupled lasers is based on serially interconnected lasers using the principle of gain quenching. The light from the dominant laser suppresses its neighboring lasers through gain saturation, but still receives amplification by the active element of the suppressed lasers, compensating for coupling losses. This light passes through each of the successive lasers, simultaneously suppressing and being amplified. By this mechanism all the other lasers are suppressed. Only one of the lasers can lase at a time, thus the state of the optical memory is determined by the wavelength of the dominant laser, as same as the first type. A five-state optical memory based on this concept is experimentally demonstrated. Moreover, we use the optical memories as a fundamental logic unit to realize sophisticated optical logic. We present an optical shift register that consists of two serially connected optical memories driven by common clock pulses. The concept is demonstrated at an operation speed of 20 kHz, which is limited by the laser cavities implemented by 10 meter long fiber pigtailed components. Furthermore, we cascade the optical shift register and an optical XOR gate to realize an optical pseudorandom number generator based on optical memories.

U2 - 10.6100/IR613180

DO - 10.6100/IR613180

M3 - Phd Thesis 1 (Research TU/e / Graduation TU/e)

SN - 90-386-1873-5

PB - Technische Universiteit Eindhoven

CY - Eindhoven

ER -

Zhang S. Optical multi-stable operations of coupled lasers. Eindhoven: Technische Universiteit Eindhoven, 2006. 124 p. Available from, DOI: 10.6100/IR613180