Haifei Xiang

Crosstalk analysis and optimization of high-speed interconnections

Crosstalk noise has become a major performance inhibitor in high speed digital system. This is especially the case in package designs, connector assemblies and circuit interconnects designs. With the simultaneous miniaturization of electronic systems and decreasing signal rise time, it is important to be able to predict major sources of crosstalk and to stay within the cross-talk budget for high-speed interconnects interfaces. In this paper, first, we focus on analyzing the crosstalk mechanism. Second, based on simulation, we propose methods to minimize crosstalk.

An electrical design and fabrication of a 12-channel optical transceiver with SiP packaging technology

This paper presents an electrical design of a 6.25Gbps×12-channel parallel optical transceiver with SiP packaging technology. Considering such high speed, a low impedance and low noise power distribution network (PDN) is designed to suppress simultaneous switching noise (SSN) and a novel embedded capacitor filter is used to replace the conventional power supply filter. To minimize the impedance discontinuity of electrical channels, a signal integrity (SI) design flow based on Electromagnetic Analysis Method and Circuit Analysis Method is proposed. Following this design flow, the high speed link performs on a large bandwidth. With the electrical design, the optical transceiver is fabricated and tested.

A 9pJ/bit SOP optical transceiver with 80 Gbps two-way bandwidth

The high-speed parallel optical transmitter module based on VCSEL/PD array, high-speed specialized integrated circuit, fiber array micro-optical components presents magnificent application and development potential. The coupling alignment between VCSEL/PD array and waveguide array has been reported using silicon optical bench (SiOB) [1–3]. In this paper, A passive coupling method based on SiOB and the packaging of the VCSEL/PD arrays are introduced; the coupling efficiency is about 80% with a misalignment tolerance of +/−15µm, optical cross talk is about −70dB. A silicon optical bench is fabricated as a platform for integrated photonic components. The thermal performance and electrical performance of optical sub-package is analyzed and optimized.

Signal integrity design and validation for multi-GHz differential channels in SiP packaging system with eye diagram parameters

Differential interconnect lines in multi-gigabits system in package (SiP) packaging system are studied in this paper. The performance of interconnect lines can be easily estimated with jitter and eye opening using the eye diagram that is very helpful metric. To maintain good eye-diagram with high voltage swing and low timing jitter, a signal integrity (SI) design flow of SiP is proposed based on eye-diagram parameters. To validate the influences of SI design to eye-diagrams, the relationship between the parameters of eye diagram and the structures of the impedance discontinuities physical elements such as vias, SMT pads are studied by a combination of software simulation and hardware validation. Some SI design rules are stipulated. As an example, a 4-channel × 10Gbp/s/channel optical transceiver in an SiP package is designed.

A new measurement method and electrical design for high density optoelectronics integration

This paper describes a parallel test method based on a cross-point switch which can be programmed to control signal path and the number of switches to be opened according to the number of channels to be tested. In this method, at the transmitting side, one source inputted cross-point switch can be fan-out to multi sources to activate device under test, and different signal trace or length of cables can change phases between multi sources. At the receiving side, all output channels are connected to another RF switch controlled to choose output channel. These two switches both are controlled by software. Multi channels working together will help evaluating cross talk between channels and SSN noise test. In this paper, to ensure test accuracy, signal integrity of DUT and test system is designed and simulated. And an 8-channel optical transceiver is tested using this method and cross talk and power noise are especially showed and analyzed. The test results indicate this test method can meet parallel optical transmission test requirement and other optical module and electrical module test; however the cost is greatly lower than high speed test instruments.

Optimization of broadband characterization for pluggable parallel optical transceiver modules on multilayer substrates

In this paper, we discuss the optimization of the high frequency performance of a parallel optical transceiver module, which is electrically pluggable, and its test board. A 6-layer printed circuit board (PCB) with embedded high-dielectric constant (Dk) material was built as a substrate for the optical transceiver module. An analysis of the signal integrity (SI) and power integrity (PI) is carried out. The RF signal quality of the differential transmission lines is demonstrated by 3-D electromagnetic simulations and 4-port Network Analyzer measurements in terms of the transmission parameter S21, the reflection parameter S11, and the time-domain reflection TDR. A 4-layer test board with 16 edge-mounted SMA connectors and one 38-pin sliding connector for optical transceiver module was also constructed. Finally, Eye-diagrams of each of the 8 channels comprising the four-channel bidirectional active optical cable (AOC) are measured.

Failure analysis and test for high speed packaging, HDMI packaging and QSFP packaging

In this paper we present several failures in optical packaging. Then we analysis the main reasons of these failures. Next, we suggest ways to avoid similar failures. Several simple examinations are also introduced. Innovative diagnostics methods are described and time saving test methods are described.

12-channel board-level multi-GHz optical link using cross-switch chips and optoelectronic multi-chip package modules

High density, large bandwidth and lower power consumption link and switch inter-system is required. Short-distance parallel optical link has become the hotspot of research because of its advantage compared with electrical link. Board communications have received a lot of attention. Most of the recent developments target 10Gbps-class systems such as super computers or high-speed IP switches. This paper demonstrates a complete short-distance parallel optical link on PCB-level based on optoelectronics multi-chip package structure for high-speed signal conversion and two cross-point chips integrated as switch used to complete signal cross-assignment. Optoelectronic package modules we fabricated are 12-channel multi-chip modules based on an advanced coupling method with high coupling efficiency. The electrical problems related to signal integrity (SI) is discussed and some simulation results are showed. To demonstrate switch inter-system, two12-channel cross-point chips are placed on PCB board, signal can be reassigned to any output channel to complete 12-channel cross-switches. The ends of 12 fibers on the board are passively aligned with VCSEL and PD. The following sections present the system design as well as measurement results.