Multichannel Realization Research Articles

Design and Realization of Multi-Channel and High-Bandwidth 2.5D Transmitter Integrated With Silicon Photonic MZM

Recently, the interconnection bandwidth of the data center is rapidly increasing. To satisfy the requirement for the high-performance data center, a 4-channel 2.5D silicon photonic transmitter is proposed and the packaging structure could increase the high-density scalability of the architecture for 1.6T/3.2T co-packaging optics (CPO) module. The electrical driver and silicon photonic Mach-Zehnder modulator (MZM) are mounted to the silicon interposer by the micro-bumps. Meanwhile, the silicon interposer is mounted to the low temperature co-fired ceramic by the solder balls. The 2.5D transmitter is assembled to the motherboard by the high-speed ball grid array (BGA) connector to make it convenient to be replaced. The electrical optimization is implemented to make the insertion loss of the whole passive link within −1.55 dB under 40 GHz, which ensures the transmitter with the socket transmit the clear simulated eye diagram at 64 Gbps PAM4 rate per channel. Moreover, the thermal evaluation is performed, which includes the heat- dissipation evaluation and the thermal-induced impact on the edge light coupling. Finally, the substrates in the 2.5D transmitter are fabricated and the transmitter is realized by the improved assembly method. By the verification of the measurement, the 2.5D transmitter we proposed could work at 64 Gbps PAM4 signal transmission rate per channel with the 6pJ/bit power consumption. Regardless of the bandwidth of the electronic integrated circuit (EIC)/MZM and the BGA connector, based on the simulation electrical bandwidth, it is potential for realizing 100 Gbps PAM4 signal transmission.

Multichannel effects in the Efimov regime from broad to narrow Feshbach resonances

We study Efimov physics of three identical bosons with pairwise multichannel interactions for Feshbach resonances of adjustable width in magnetic field. We find that the two-body multichannel realization of the interaction can affect the universal Efimov spectrum, especially for resonances of intermediate width. We analyze two scenarios that are equivalent on the two-body level but differ in their realization in three-body multichannel spin space. The deviations in the Efimov spectra of these scenarios are caused by trimer states in the closed interaction channels whose binding energy and coupling strength to the Efimov states depend on the spin realization. However, in the narrow resonance limit the Efimov spectrum is set by the resonance width parameter ${r}^{*}$ only and does not depend on the realization in spin space. We find this limit to be even independent of the interaction potential considered. In the broad resonance limit all excited Efimov trimer energies approach the ones from the corresponding single-channel system for the scenarios investigated.

On mitigating acoustic feedback in hearing aids with frequency warping by all-pass networks

Acoustic feedback due to the acoustic coupling between the microphones and loudspeakers at high gains can cause the hearing aid system to become unstable. This instability results in brief “howling” artifacts as magnitude and phase conditions fulfill the Nyquist stability criterion (NSC). We present a novel approach that uses all-pass networks to perform nonlinear spectral mapping that we call “freping,” a portmanteau for frequency warping. In this contribution, we focus on spectral manipulations on top of adaptive feedback cancellation (AFC) to break NSC for improved feedback reduction. A real-time, multichannel realization is presented, which has individual control of the warping degree in each frequency band. Freping helps mitigate the NSC and thus leads to improved feedback control, while distortions due to freping are fairly benign based on informal subjective assessments. Our current findings indicate that improvements in terms of the perceptual evaluation of speech quality (PESQ) and the hearing-aid speech quality index (HASQI) can be achieved with freping for a basic AFC (PESQ: 2.56 to 3.52 and HASQI: 0.65 to 0.78) at medium amplification; and an advanced AFC (PESQ: 2.75 to 3.17 and HASQI: 0.66 to 0.73) at high amplification. Additional results will be included in the final presentation.

Realization of Multi-Channel, High-Speed Waveform Generator Based on FPGA

This paper introduces the design and realization of a multi-channel high-speed waveform generator based on FPGA, Which consists of the high-speed clock generator, the high-speed high-precision digital to analog converter, multi-stage pipeline accumulator and high-speed small signal conditioning. At last, it gives some simulation. The results show that the output signal type of this waveform generator is rich, and the maximum output frequency is 80MHz. The waveform generator can be used in the fields which require multi-channel high-speed signal, such as phased array radar.

A BiCMOS time interval digitizer based on fully-differential, current-steering circuits

A time interval digitizer cell with a 0-16 ns input range and a nominal LSB width of 1.0 ns has been integrated in a 2-/spl mu/m BiCMOS technology, The circuit exhibits both integral and differential nonlinearity below 0.15 LSB and a timing error of 0.32 ns RMS. Logic gate propagation delays are used as time measurement units, and the nominal value of the delays is set by an on-chip phase-locked loop (PLL). Fully-differential, current-steering circuits with low voltage swings are used to implement the time interval digitizer so as to generate minimal switching noise. The cell is to be used in the monolithic, multi-channel realization of a high-sensitivity, mixed-signal data acquisition front-end. By virtue of the time digitization architecture used, the average power dissipation of the cell is only 19.8 mW, despite the use of circuits that dissipate static power, and the layout area is a compact 448 /spl mu/m/spl times/634 /spl mu/m.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>