Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Physical Review A

Intensity-noise properties of injection-locked lasers

C. C. Harb, Timothy C. Ralph, Elanor H. Huntington, Ingo Freitag, David E. McClelland, Hans‐A. Bachor

Published Nov 1, 1996• 71 citations
Publisher

Abstract

We present experimental results that illustrate how laser intensity noise near the quantum-noise limit is transferred in an injection-locked cw Nd:(yttrium aluminum garnet) nonplanar ring-oscillator laser. We show that these results are in extremely good agreement with our quantum-mechanical model describing the injection locking process [T. C. Ralph, C. C. Harb, and H.-A. Bachor, Phys. Rev. A]. Three regions in the intensity-noise spectrum are identified and we show that different minimum noise levels exist in these regions. Finally, we show that the injection-locked laser can generate and preserve nonclassical states. \textcopyright{} 1996 The American Physical Society.

DOI
10.1103/physreva.54.4370

Related papers

Experimental and Theoretical Investigations on the Intensity Noise Properties of Injection-Locked Lasers

Ingo Freitag, Andreas Tünnermann, H. Welling +4 more

Experimental investigations illustrating the intensity noise properties of injection-locked solid-state lasers were performed. The measured results are predicted by a quantum mechanical model. The theory describes the intensity noise transfer to the slave laser’s output for large modulation signals as well as for signals at the quantum noise level. Different frequency regions in the intensity noise spectrum are identified and it is shown that there exist different minimum noise levels in these regions. Under appropriate conditions, injection-locked lasers can generate non-classical light.

Advanced Solid-State Lasers•Jan 1, 1996•0 citations

Intensity noise of injection-locked lasers: Quantum theory using a linearized input-output method

Timothy C. Ralph, C. C. Harb, Hans‐A. Bachor

We derive analytical expressions for the quantum-noise spectra of an atomic laser using a linearized input-output method. We generalize the method to the problem of injection-locked lasers. We identify three distinct spectral noise regimes in the solution, unifying previous results. The approach offers insights into the physical processes and is especially suited for comparison with experiment. The quantum spectral noise properties of the pump laser and the injected laser appear explicitly in the solution. \textcopyright{} 1996 The American Physical Society.

Physical Review A•Nov 1, 1996•62 citations

Squeezing in an injection-locked semiconductor laser

Shuichiro Inoue, S. Machida, Y. Yamamoto +1 more

The intensity-noise properties of an injection-locked semiconductor laser were studied experimentally. The constant-current-driven semiconductor laser producing the amplitude-squeezed state whose intensity noise was reduced below the standard quantum limit (SQL) by 0.72 dB was injection-locked by an external master laser. The measured intensity-noise level of the injection-locked semiconductor laser was 0.91 dB below the SQL. This experimental result indicates that a phase-coherent amplitude-squeezed state or squeezed vacuum state together with a reference local oscillator wave can be generated directly by semiconductor laser systems.

Physical Review A•Sep 1, 1993•37 citations

Feedback control of laser intensity noise

B. C. Buchler, Elanor H. Huntington, C. C. Harb +1 more

A fully quantum-mechanical model of feedback to the pump source of a four-level laser is developed with a view to predicting the achievable intensity noise reduction. For solid-state lasers, the model shows that quantum noise sources due to laser dynamics have a significant impact on the optimization of the feedback loop. Experimental results obtained with a diode pumped neodymium:yttrium aluminum garnet (Nd:YAG) laser are found to be in good agreement with the theoretical model. The ultimate limit to the noise suppression comes from the quantum noise due to the measurement processes in the feedback loop. A scheme to overcome this limit using a squeezed vacuum is theoretically demonstrated to be a highly efficient method of generating bright intensity squeezed light, particularly in the kHz regime where bright squeezing is otherwise difficult to obtain.

Physical Review A•Feb 1, 1998•40 citations

Master-equation theory of multimode semiconductor lasers. II. Injection locking

Andrea Eschmann, Crispin W. Gardiner

The master-equation theory for multimode semiconductor lasers [A. Eschmann and C. W. Gardiner, Phys. Rev. A 54, 760 (1996)] is adapted to treat the case of an injection-locked laser. Both the intensity noise and the phase noise of the system are examined. A decrease in the total intensity noise and in the inten- sity noises of the individual modes is found for increasing injection power, provided the injection signal does not dominate the entire system. A regime is found in which a reduction of the intensity noise below the shot noise level is obtained which is not single-mode squeezing, but which is due to anticorrelations between the individual modes, and a further regime in which true single-mode squeezing exists is also found. The phase noise is found to decrease with increasing injection strength, in other words as phase locking occurs. \textcopyright{} 1996 The American Physical Society.

Physical Review A•Oct 1, 1996•7 citations

Nonclassical amplitude-squeezed light generated by semiconductor quantum well lasers

Daniel C. Kilper, Michael J. Freeman, Duncan G. Steel +2 more

Amplitude-squeezed light has been generated by semiconductor quantum well lasers in numerous optical configurations, at both room and cryogenic temperatures. Various intensity noise sources associated with nonideal laser operation, in particular mode partition and polarization-dependent noise, can introduce intensity fluctuations that limit or remove amplitude squeezing. We discuss amplitude noise reduction in low-temperature free-running and injection-locking laser configurations and room-temperature injection locking and external-cavity laser configurations. Drive-current modulation with a nonclassical SNR improvement is achieved with an injection-locked laser.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Apr 26, 1995•3 citations
We present experimental results that illustrate how laser intensity noise near the quantum-noise limit is transferred in an injection-locked cw Nd:(yttrium aluminum garnet) nonplanar ring-oscillator laser. We show that these results are in extremely good agreement with our quantum-mechanical model describing the injection locking process [T. C. Ralph, C. C. Harb, and H.-A. Bachor, Phys. Rev. A]. Three regions in the intensity-noise spectrum are identified and we show that different minimum noise levels exist in these regions. Finally, we show that the injection-locked laser can generate and preserve nonclassical states. \textcopyright{} 1996 The American Physical Society.
Experimental investigations illustrating the intensity noise properties of injection-locked solid-state lasers were performed. The measured results are predicted by a quantum mechanical model. The theory describes the intensity noise transfer to the slave laser’s output for large modulation signals as well as for signals at the quantum noise level. Different frequency regions in the intensity noise spectrum are identified and it is shown that there exist different minimum noise levels in these regions. Under appropriate conditions, injection-locked lasers can generate non-classical light.
We derive analytical expressions for the quantum-noise spectra of an atomic laser using a linearized input-output method. We generalize the method to the problem of injection-locked lasers. We identify three distinct spectral noise regimes in the solution, unifying previous results. The approach offers insights into the physical processes and is especially suited for comparison with experiment. The quantum spectral noise properties of the pump laser and the injected laser appear explicitly in the solution. \textcopyright{} 1996 The American Physical Society.
The intensity-noise properties of an injection-locked semiconductor laser were studied experimentally. The constant-current-driven semiconductor laser producing the amplitude-squeezed state whose intensity noise was reduced below the standard quantum limit (SQL) by 0.72 dB was injection-locked by an external master laser. The measured intensity-noise level of the injection-locked semiconductor laser was 0.91 dB below the SQL. This experimental result indicates that a phase-coherent amplitude-squeezed state or squeezed vacuum state together with a reference local oscillator wave can be generated directly by semiconductor laser systems.
A fully quantum-mechanical model of feedback to the pump source of a four-level laser is developed with a view to predicting the achievable intensity noise reduction. For solid-state lasers, the model shows that quantum noise sources due to laser dynamics have a significant impact on the optimization of the feedback loop. Experimental results obtained with a diode pumped neodymium:yttrium aluminum garnet (Nd:YAG) laser are found to be in good agreement with the theoretical model. The ultimate limit to the noise suppression comes from the quantum noise due to the measurement processes in the feedback loop. A scheme to overcome this limit using a squeezed vacuum is theoretically demonstrated to be a highly efficient method of generating bright intensity squeezed light, particularly in the kHz regime where bright squeezing is otherwise difficult to obtain.
The master-equation theory for multimode semiconductor lasers [A. Eschmann and C. W. Gardiner, Phys. Rev. A 54, 760 (1996)] is adapted to treat the case of an injection-locked laser. Both the intensity noise and the phase noise of the system are examined. A decrease in the total intensity noise and in the inten- sity noises of the individual modes is found for increasing injection power, provided the injection signal does not dominate the entire system. A regime is found in which a reduction of the intensity noise below the shot noise level is obtained which is not single-mode squeezing, but which is due to anticorrelations between the individual modes, and a further regime in which true single-mode squeezing exists is also found. The phase noise is found to decrease with increasing injection strength, in other words as phase locking occurs. \textcopyright{} 1996 The American Physical Society.
Amplitude-squeezed light has been generated by semiconductor quantum well lasers in numerous optical configurations, at both room and cryogenic temperatures. Various intensity noise sources associated with nonideal laser operation, in particular mode partition and polarization-dependent noise, can introduce intensity fluctuations that limit or remove amplitude squeezing. We discuss amplitude noise reduction in low-temperature free-running and injection-locking laser configurations and room-temperature injection locking and external-cavity laser configurations. Drive-current modulation with a nonclassical SNR improvement is achieved with an injection-locked laser.