Résumé. L’apprentissage non supervisé a classiquement pour objectif la détection de sous-populations homogènes (classes) sans information a priori sur celles-ci. Les classes sont considérées de manière équivalente. Le problème étudié dans cet article est quelque peu distinct. On s’intéresse uniquement à une sous-population d’intérêt dans l’échantillon étudié que l’on cherche à identifier avec u...

In this paper, a miniaturized planar rat-race coupler is proposed to achieve arbitrary power division ratio and harmonic suppression performance simultaneously. It consists of six enhanced Tshaped line sections. The T-shaped lines can be equivalent to arbitrary electrical length lines rather than the conventional λ/4 lines. The explicit design formulas are derived and the characteristic impedan...

Low current sensitivity and insufficient system stability are two key problems in all-fiber current sensor (AFCS) studies. In order to solve the two problems, a novel AFCS combining single-polarization single-mode (SPSM) couplers and a loop structure is presented in this paper with a design that incorporates the advantages of both SPSM couplers and a loop structure. SPSM couplers are shown to s...

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The propagation of the light that is emitted from both the tunable Ti:Sapphire laser (single mode) and the Coherent FAPs (multimode) is found to be modeled very well using gaussian optics. This is useful when trying to obtain a beam of a certain size at some prescribed distance from a converging lens. This technote will describe (1) gaussian optics, (2) how to calculate the beam radius after pa...

Analytical expressions are derived which relate the optical bandwidth and the fabrication tolerances of multimode interference (MMI) couplers to their most important design parameters. These expressions compare adequately with mode analysis simulations. For strong guided structures, the optical bandwidth is shown to be inversely proportional to the number of input and output ports N and to the ...

A 3–8 GHz delay-locked loop (DLL) with cycle jitter calibration is presented. To lower the operation frequency of a voltage-controlled delay line (VCDL), this DLL adopts the dividers, an edge combiner, and the multiple VCDLs. A duty cycle correction circuit is presented to maintain the output duty cycle of 50%. This DLL has been fabricated in 90-nm CMOS process. The measured peak-to-peak jitter...

Finite two-dimensional photonic bandgap (PBG) structures were analyzed with a ®nite-difference time-domain (FDTD) full wave, vector Maxwell equation simulator. Removal of particular portions of these PBG structures lead to interesting sub-micron-sized waveguiding environments. Several waveguides and power dividers were designed and evaluated. By introducing further defects into the PBG waveguid...