Author
Joseph F. Weller
Bio: Joseph F. Weller is an academic researcher from United States Naval Research Laboratory. The author has contributed to research in topics: Laser & Injection locking. The author has an hindex of 25, co-authored 65 publications receiving 2044 citations.
Papers
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TL;DR: Heterodyne detection of the light from two slave lasers injection locked to FM sidebands of a modulated master laser is used to generate a narrowband microwave signal at 10.5 GHz.
Abstract: Heterodyne detection of the light from two slave lasers injection locked to FM sidebands of a modulated master laser is used to generate a narrowband microwave signal at 10.5 GHz.
345 citations
TL;DR: Optical feedback-induced changes in the output spectra of several GaAlAs laser operating at 0.83 μm are described in this paper. But this work is restricted to a three-mirror cavity, where the feedback radiation from a mirror 60 cm away from the laser is controlled in intensity and phase.
Abstract: Optical feedback-induced changes in the output spectra of several GaAlAs lasers operating at 0.83 μm are described. The feedback radiation obtained from a mirror 60 cm away from the laser is controlled in intensity and phase. Spectral line narrowing or broadening is observed in each laser depending on the feedback conditions. Minimum linewidths observed with feedback are less than 100 kHz. Improved wavelength stability is also obtained with optical feedback resulting in 15 dB less phase noise. An analytical model for the three-mirror cavity is developed to explain these observations.
226 citations
TL;DR: In this paper, the control of the far-field beam pattern and the spectrum of a 10-element laser diode array by injection locking to a single-mode master laser is described.
Abstract: The control of the far‐field beam pattern and the spectrum of 10‐element laser diode array by injection locking to a single‐mode master laser are described. With less than 3 mW of injected power an array output of 105 mW at a single frequency with a 0.5° wide far‐field lobe is obtained. Similar results are observed when the entire array is illuminated by the master laser beam, or when only one of the stripes is illuminated. The narrow lobe contains 60–70% of the total power and is centered at an angle of about 4° relative to the normal of the array facet.
158 citations
TL;DR: In this article, offset phase-locking of two Nd:YAG nonplanar ring laser by electronic feedback was reported, and the difference frequency was continuously tunable in three bands from 6 to 34 GHz and exhibits a hold-in range and linewidth of 82 MHz and < 1 mHz, respectively.
Abstract: We report offset phase-locking of two Nd:YAG nonplanar ring lasers by electronic feedback. The difference frequency is continuously tunable in three bands from 6 to 34 GHz and exhibits a hold-in range and linewidth of 82 MHz and <1 mHz, respectively.
124 citations
TL;DR: In this paper, a new technique for sinusoidal intensity modulation of light, based on injection-locking of two longitudinal modes of a single laser to FM sidebands of another laser, is described.
Abstract: A new technique for sinusoidal intensity modulation of light, based on injection-locking of two longitudinal modes of a single laser to FM sidebands of another laser, is described. A 35 GHz microwave signal with a linewidth of less than 10 Hz was generated.
114 citations
Cited by
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TL;DR: Recent findings indicate that network oscillations bias input selection, temporally link neurons into assemblies, and facilitate synaptic plasticity, mechanisms that cooperatively support temporal representation and long-term consolidation of information.
Abstract: Clocks tick, bridges and skyscrapers vibrate, neuronal networks oscillate. Are neuronal oscillations an inevitable by-product, similar to bridge vibrations, or an essential part of the brain’s design? Mammalian cortical neurons form behavior-dependent oscillating networks of various sizes, which span five orders of magnitude in frequency. These oscillations are phylogenetically preserved, suggesting that they are functionally relevant. Recent findings indicate that network oscillations bias input selection, temporally link neurons into assemblies, and facilitate synaptic plasticity, mechanisms that cooperatively support temporal representation and long-term consolidation of information.
5,512 citations
Proceedings Article•
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TL;DR: In this article, the performance requirements for externally-modulated analog microwave photonic links are reviewed with specific emphasis placed on modulator efficiency, laser noise, detected photocurrent, and link linearity.
Abstract: An overview of analog microwave photonics will be presented. The performance requirements for externally-modulated analog microwave photonic links will be reviewed with specific emphasis placed on modulator efficiency, laser noise, detected photocurrent, and link linearity.
1,434 citations
Journal Article•
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TL;DR: In this paper, techniques developed in the last few years in microwave photonics are reviewed with an emphasis on the systems architectures for photonic generation and processing of microwave signals, photonic true-time delay beamforming, radio-over-fiber systems, and photonic analog-to-digital conversion.
Abstract: Broadband and low loss capability of photonics has led to an ever-increasing interest in its use for the generation, processing, control and distribution of microwave and millimeter-wave signals for applications such as broadband wireless access networks, sensor networks, radar, satellite communitarians, instrumentation and warfare systems. In this tutorial, techniques developed in the last few years in microwave photonics are reviewed with an emphasis on the systems architectures for photonic generation and processing of microwave signals, photonic true-time delay beamforming, radio-over-fiber systems, and photonic analog-to-digital conversion. Challenges in system implementation for practical applications and new areas of research in microwave photonics are also discussed.
1,332 citations
13 Apr 1982
TL;DR: The current state of the art of optical fiber sensors is reviewed, the principles of operation are detailed and the various types of fiber sensors are outlined.
Abstract: The current state of the art of optical fiber sensors is reviewed. The principles of operation are detailed and the various types of fiber sensors are outlined. Achievable performance and limitations are discussed and a description of technology used to fabricate the sensor is presented. The characteristics of acoustic, magnetic, gyro, laser diode, and other sensors are described. Trends in the development of this sensor technology and expected application areas are briefly outlined.
817 citations
TL;DR: In this article, the effects of feedback on the spectra of 1.5-μm DFB lasers from feedback power ratios as low as -80 dB up to -8 dB were measured.
Abstract: We have measured the effects of feedback on the spectra of 1.5-μm DFB lasers from feedback power ratios as low as -80 dB up to -8 dB. Five distinct regimes of effects are observed with well defined transitions between them. The dependence of these effects on the distance to the reflection is also investigated.
729 citations