Simulations of Thermomechanical Stresses and Optical Misalignment in 1550-nm Transmitter Optoelectronic Modules Using FEM and Process Dispersions

Abstract

Expertise of packaging for optoelectronic components requires the solution of optical, mechanical, and electrical problems in the same way. The purpose of this paper is to present three-dimensional simulations using finite-element method (FEM) of thermomechanical stresses and strains in 1550-nm laser modules induced by Nd:YAG crystal laser welds and thermal cycles on main subassembly laser submount. Nonlinear FEM computations, taking into account of experimental ( ) measured curves, show that thew laser welding process can induce high level of strains in columns of the laser platform, bearing the laser diode, responsible of an optical axis shift and a gradual drop of the optical power in relation with relaxation of accumulated stresses in the subassembly (W. M. Sherry et al., "High performance optoelectronic packaging for 2.5 and 10 Gb/s laser modules," in Proc. Electron. Compon. Technol. Conf., 1996, pp. 620-627). Typical stresses are close to 160 MPa with drift about 5 MPa with the dispersion of energy level of the laser Nd: YAG beam. The introduction of both material and process dispersion in order to evaluate their impact on product lifetime distribution has been taking into account. In the case of thermal cycles, stresses can occur on elements sensitive to coefficient of thermal expansion mismatches such as solder joints between the laser platform and thermoelectric cooler and as fiber glued into the pigtail leading to crack propagation with sudden drop of optical power. A previous paper demonstrated that laser submount is the most sensitive part of optical system (Deshayes, et al., "Three-dimensional FEM simulations of thermal mechanical stresses in 1.55 m laser modules," Microelectron. Rel., vol. 43, no. 7, pp. 1125-1136, Jul. 2003). Experimental analyses were also conducted to correlate simulation results and monitor the output optical power of laser modules after 500 thermal cycles ( 40 C + 85 C VRT). Index Terms-Distributed feedback (DFB), finite-element model (FEM), laser YAG, neodymium-doped yttrium aluminium garnet (NdYAG), optical module, reliability, welding.

Finite Element Thermomechanical Modeling of Large Area Thermoelectric Generators based on Bismuth Telluride Alloys

“…The sensitivity of solders to thermal cycling has been identified as one of the major causes of device failure. 6,7 Even for severe conditions corresponding to a DT of 100°C between the hot and cold sides, the maximum simulated stress level stays below the strength of the TE materials.…”

Parameters Optimization of Er³⁺ Doped Fiber Amplifier by Numerical Simulation

“…Furthermore, for the EDF, its initial parameters are designed as that the length is 5 m, the NA value is 0.24, and erbium ion density is 1×10 25 m -3 , respectively. According to Ref [4][5][6][7], not only the pumping power, but the length and density of EDF have the obvious effect to the output features of EDFA. Nevertheless, due to the density of erbium ion is constant in Optisystem, we then model the output performance of the EDFA system in Fig.…”

“…Ref [3] uses the SPICE2 software to analyze light transmission system. And Ref [4][5][6] simulate the features of laser diode and fiber laser by rate equations and the professional simulation software, respectively. Our group has also achieved to study and optimize the output performance of fiber Raman amplifier (FRA) by using the Optisystem software [7].…”

Performance Optimization Based Spectrum Analysis on Optical Fiber Raman Amplifier with Backward Pumping

“…On the other hand, because of the high cost at the optical devices and analyzer, it is a hard work to conduct the spectrum analysis of OFRA system though adopting the traditional experiments. To overcome such problems, some researches by the simulation way have been used in the performance analysis of the optical devices, which is with the advantages of low complexity, fast speed, flexible configuration and vision [6][7][8]. For instance, Ref [6] uses the SPICE2 software to analyze light transmission system.…”

“…For instance, Ref [6] uses the SPICE2 software to analyze light transmission system. Ref [7] and Ref [8] simulate the features of 1550nm fiber laser. Our group also achieved to analyze and optimize the output performance of 1550nm fiber laser and the superfluorescent source by simulation based on Giles model [4,5].…”