Jicheng Hu

Rate-equation-based VCSEL model and simulation

Vertical-Cavity Surface-Emitting Lasers (VCSELs) are a new generation of semiconductor lasers that have many advantages. In this paper, we present a comprehensive circuit-level VCSEL model that addresses the basic spatial and thermal behavior of VCSELs based on the rate equations without sacrificing the numerical efficiency demanded by the circuit-level simulation of optoelectronic systems. The model is implemented into SPICE-like simulators, and the simulated results exhibit a good agreements with references.

Multimode rate-equation-based VCSEL thermal and spatial model of circuit level

In recent years, the characteristics of VCSELs have improved enormously that they have attracted more considerable interest. The corresponding developments of circuit-level VCSEL models are required for use in the design and simulation of optoelectronic applications. Unfortunately, existing models lack either the computational efficiency or the comprehensiveness warranted. In this paper, we present a VCSEL model that addresses the spatial dependent and thermal behavior of VCSELs based on multimode rate equations without sacrificing the numerical efficiency demanded by the circuit-level simulation of optoelectronic systems. Moreover, the thermal behavior is modeled by a laser diode based on Tuckers model with the parameters extracted directly by method of Gao and temperature dependent parasitic resistor and reverse saturation current are also considered. The equivalent circuit of the model is given and it is implemented into SPICE-like simulators to simulate the dc, ac and transient features of a 863nm bottom-emitting AlGaAs VCSEL. The simulated results exhibit good agreements with references.

A new circuit model of multi-quantum well Vertical-Cavity Surface-Emitting Lasers

In this paper, a new high order circuit model of multi-quantum well Vertical-Cavity Surface-Emitting Lasers (VCSEL) based on a modified rate-equation is presented. This model is accounts for both thermal and spatial dependences of VCSEL characteristics. A new logarithmic relation of optical gain on carrier density substitutes for the linear relation in the conventional rate equation for quantum well lasers. A four-term Bessel-series expansion for the VCSEL carrier number is utilized to achieve good accuracy. A zero-order Laguerre-Guassian beam is utilized for describing the photo distribution to simplify the computation. This model can be readily used in SPICE-like circuit simulators. Numerical examples are introduced to replicate the multi-quantum well VCSELs typical dc, Small-signal and transient operation, including temperature-dependent light-current (LI) curves, modulation responses, and diffusive turn-off transients. Furthermore, we verify our model against other lower order model from reported in the literature.

A New Circuit-Level Thermal Model of Vertical-Cavity Surface-Emitting Lasers

In this paper, a new high order equivalent circuit model of Vertical-Cavity Surface-Emitting Lasers (VCSEL) based on rate-equation is presented. This model accounts for the thermal and spatial dependence of a VCSEL’s behavior. We implemented it in circuit simulation program Pspice, and replicate its typical dc, Small-signal and transient operation, including temperature-dependent light-current (LI) curves, modulation responses, and diffusive turn-off transients.

ϵ-Algorithm for Transient Analysis of Lossy and Dispersive Multiconductor Transmission Lines

A novel approach for transient analysis of coupled transmission line circuits is presented. A recursive ϵ-algorithm is constructed to accelerate the evaluation of the generalized inverse matrix Pade approximation to exponential function (GIMPAe). Then the frequency-domain responses is transformed into the time domain. Both transient responses on the ends of the transmission lines and along the transmission lines are given. The numerical results prove the new approach is efficient and accurate for treating coupled, lossy, nonuniform and dispersive multiconductor transmission line circuits.

A study on angular resolving powers of cross-loop/monopole antenna arrays based on MUSIC algorithm

To increase HF-GWR portability, it is very desirable to use smaller antenna yet achieve higher angular resolving power. Based on MUSIC algorithm, the angular resolving powers of various combined cross-loop/monopole and monopole antenna arrays are studied. It is found that a combination of two cross-loop/monopole antennas plus one monopole antenna gives the best performance.