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The talk will focus on advances in high brightness single longitudinal/transverse mode master oscillator power amplifier (MOPA) QCls and MOPA QCL arrays capable of broadband tuning, as well as on low-divergence high brightness QCLs with plasmonic collimators. Specifically we will report on multi-wavelength arrays of master-oscillator power-amplifier quantum cascade lasers operating at wavelengths...
The design and characterization of a silicon-on-insulator planar concave grating based (de)multiplexer operating at 3.8µm is reported. Low insertion loss (≈1.6dB) and good crosstalk characteristics (≈19dB) are demonstrated.
Mode transformers between very compact substrate removed waveguides and very big polymer waveguides were designed and fabricated. Transition loss between two types of waveguides was quantified and 7 dB insertion loss improvement was measured.
In this paper we describe Ge-on-Si waveguides and Mach-Zehnder interferometers operating in the 5.2 – 5.4 µm wavelength range. 3dB/cm waveguide losses and Mach-Zehnder interferometers with 20dB extinction ratio are presented.
We overview our studies on emission of quantum dots coupled to photonic metamaterials. We reveal how the interactions of the quantum dots simultaneously with the magnetic and the electric resonances of the metamaterials affect their spontaneous emission and result in eliptically polarized light emission at off-normal directions.
We demonstrate a platform for monolithic integration of active and low loss passive components. The passive section is realized by removal of the quantum wells. Characterization results of lasers with passive DBR reflectors are presented.
We report on scalable bidirectional optical coupling between silicon-on-insulator waveguides and polymer waveguides. Coupling loss of 0.8 dB and ±2 µm misalignment loss of 0.3 (0.6) dB are measured at TM (TE) polarization states.
The performance improvement of direct-detection double-sideband OFDM systems achieved by using symbol precoding to reduce the signal PAPR is assessed experimentally. EVM improvement of about 2 dB, and SSMF reach increase of 15% are shown.
This paper describes a method for optical OFDM symbol synchronization using virtual subcarriers as an indicator of symbol starting point. It offers a reduction in DSP complexity and bandwidth overhead which makes it suitable for practical implementation.
Digital coherent transceivers are potentially a disruptive technology for the optical access network. The salient features of a digital coherent optical access network are discussed, in addition to the photonic technology and DSP required for realization.
Nonlinear compensation based on digital backward propagation (DBP) is numerically implemented in 200 Gb/s polarization multiplexed (PM) PM-m-QAM un-compensated transmission. The impact of reduced ADC oversampling and quantization on DBP performance is analyzed.
We propose a novel training-aided feed-forward fre-quency-offset estimation method based on CAZAC sequences. The precision and robustness of the estimator is evaluated with respect to CD and PMD for frequency offsets up to ±3.6 GHz.
Bit interleaved coded modulation with four dimensional mapping using single parity check coding is discussed for high spectral efficiency transoceanic transmission systems.
Several attractive classes of LDPC codes including quasi-cyclic (QC), convolutional, staircase, and spatially-coupled codes are described. We show that these classes of LDPC codes can be derived from QC-LDPC code design. We demonstrate that record coding gains can be obtained from properly designed irregular QC-LDPC codes.
TCM-QPSK concatenated with a properly designed outer LDPC code is evaluated and compared against LDPC-coded BPSK. Simulation results show that BER performance of the former is 0.8 dB better than that of the latter.
Phase mask encryption is proposed to improve the transmission privacy of an optical steganography system. The stealth signal carried by amplified spontaneous emission noise is encrypted by a fast changing code.
We compare the accuracy of recently-published closed-form expressions for the nonlinear noise in coherent PDM-QPSK and PDM-16QAM optical systems without in-line chromatic dispersion compensation against the numerical solution of the vector nonlinear Schrödinger equation and show their limitations.
Optical refrigeration is based on anti-Stokes fluorescence, a process in which a material absorbs light near one frequency and then fluoresces at a higher mean frequency. In a solid this process removes phonons to furnish the energy difference between the absorbed and emitted light and thereby cools the material. The best optical refrigeration results have been achieved by using transparent solids...
Laser cooling of solids based on anti-Stokes photoluminescence was proposed in 1929 [1]. Indeed, through the light emission based on phonon-assisted anti-Stokes photoluminescence, the average photon energy emitted is larger than that for the absorbed pump photons. The difference between the emitted and absorbed photon energies is made up by the energy of each removed phonon. Since phonons represent...
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