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Linear optical elements are pivotal instruments in the manipulation of classical and quantum states of light. The vast progress in integrated quantum photonic technology enables the implementation of large numbers of such elements on chip…

Quantum Physics · Physics 2016-10-10 Max Tillmann , Christian Schmidt , Philip Walther

The ergodic spectral efficiency (SE) in interference-limited multiple-input multiple-output (MIMO) downlink cellular systems is characterized based on stochastic geometry. A single user is served by using singular value decomposition…

Information Theory · Computer Science 2016-11-01 Jinseok Choi , Jeonghun Park , Brian L. Evans

The impact of nonlinear refraction and residual absorption on the achievable peak and average power in beam-splitter-based coherent beam combination is analyzed theoretically. While the peak power remains limited only by the aperture size,…

Quantum control in large dimensional Hilbert spaces is essential for realizing the power of quantum information processing. For closed quantum systems the relevant input/output maps are unitary transformations, and the fundamental challenge…

Quantum Physics · Physics 2014-10-17 B. E. Anderson , H. Sosa-Martinez , C. A. Riofrío , I. H. Deutsch , P. S. Jessen

We investigate the capacity of opportunistic communication in the presence of dynamic and distributed spectral activity, i.e. when the time varying spectral holes sensed by the cognitive transmitter are correlated but not identical to those…

Information Theory · Computer Science 2010-04-27 Syed A. Jafar , Sudhir Srinivasa

We report on the development of a frequency modulatable 795 nm semiconductor laser based on self-injection locking to a high quality factor whispering gallery mode microresonator. The laser is characterized with residual amplitude…

Due to coherent population oscillation (CPO) effect, we theoretically examine the generation and manipulation of Laguerre-Gaussian beams in terms of phase and amplitude modulation respectively in semiconductor quantum dots (SQDs). The…

Quantum Physics · Physics 2009-11-18 Wen-Ming Ju , Ka-Di Zhu , Huan Wang , Pei-Hao Huang

We study the competing effects of stimulated and spontaneous emission on the information capacity of an amplifying disordered waveguide. At the laser threshold the capacity reaches a "universal" limit, independent of the degree of disorder.…

Quantum Physics · Physics 2007-05-23 J. Tworzydlo , C. W. J. Beenakker

Coherent control of wave transmission and reflection is crucial for applications in communication, imaging, and sensing. However, many practical scenarios involve partially coherent waves rather than fully coherent ones. We present a…

Optics · Physics 2024-08-13 Cheng Guo , Shanhui Fan

We investigate how unitary control can improve parameter estimation by designing the effective spectrum of the imprinting Hamiltonian. We show that, for commuting Hamiltonians, the general problem of spectral manipulation via unitary…

Quantum Physics · Physics 2025-11-17 Paul Aigner , Wolfgang Dür

We report shifting of the frequency of an 850 nm laser with an instantaneous bandwidth of (350-1650), MHz and an efficiency between 35% (minimum) to 80% (best at frequencies around 600 and 1500, MHz) by phase modulation with a sawtooth…

Optics · Physics 2009-10-10 Rachel Houtz , Cheong Chan , Holger Mueller

Analyze of experimental results shows that the energy discharge efficiency of the modern modulators is 0.92-0.93. The energy transfer efficiency can be reached up to 0.7 for 1.5 usec pulse width and up to 0.8 for 3.0 usec accordingly. The…

Accelerator Physics · Physics 2007-05-23 Anatoly Krasnykh

Broadband wavelength tuneability can ensure a new level of versatility for laser systems and extend areas of their applications. Principle limitations of achieving wide tuning wavelength ranges are generally defined by the spectral…

One way to interpret the reasoning power of transformer-based language models is to describe the types of logical rules they can resolve over some input text. Recently, Chiang et al. (2023) showed that finite-precision transformers can be…

Machine Learning · Computer Science 2025-09-12 William Merrill , Ashish Sabharwal

Orbital angular momentum is a fundamental degree of freedom of light that manifests itself even at the single photon level. The coherent generation and beaming of structured light usually requires bulky and slow components. Using wave…

Two novel 5.5 bit/4D modulation formats are experimentally demonstrated to transmit over 9680 km of SSMF. A reach increase of 29.4% over the 6 bit/4D PM-8QAM is shown. Furthermore, increased nonlinear tolerance with respect to PM-8QAM is…

Signal Processing · Electrical Eng. & Systems 2020-11-02 Sjoerd van der Heide , Bin Chen , Menno van den Hout , Hartmut Hafermann , Ton Koonen , Alex Alvarado , Chigo Okonkwo

Token uniformity is commonly observed in transformer-based models, in which different tokens share a large proportion of similar information after going through stacked multiple self-attention layers in a transformer. In this paper, we…

Computation and Language · Computer Science 2023-12-20 Hanqi Yan , Lin Gui , Wenjie Li , Yulan He

We establish an upper bound on the noncoherent capacity pre-log of temporally correlated block-fading single-input multiple-output (SIMO) channels. The upper bound matches the lower bound recently reported in Riegler et al. (2011), and,…

Information Theory · Computer Science 2011-09-14 Wei Yang , Giuseppe Durisi , Veniamin I. Morgenshtern , Erwin Riegler

Tunable lasers are essential for optical communication, spectroscopy, and precision sensing, where flexible and fast control of the laser wavelength is needed. However, conventional tunable laser systems often rely on mechanical actuation,…

Utilization of the spatial degree of freedom vastly enhances informational capacity of light at the cost of stringent requirements on the processing devices. Multi-mode quantum memories constitute a viable candidate for quantum and…

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