摘要:

An analysis of phase-locked laser arrays has been performed to determine the injection currents required to select a specified array super-mode at a given optical output power for the array. The model developed is applicable to both uniform and chirped arrays (where the stripe width and/or the inter-element separation may vary). The relative merits of these two kinds of laser arrays are compared.

DOI:10.1049/ip-j.1987.0012

出版商:IEE    

年代:1987

数据来源: IET

摘要:

We review the theory necessary to describe the class of semiconductor lasers with nonplanar mirrors whose resonator geometry is of the unstable resonator configuration. We present formulas from geometrical unstable resonator theory and calculate quantities relevant to semiconductor lasers, including quantum efficiency and the width limitation due to total internal reflection. We describe the mirror coupled mode formalism for analysing the modes of unstable res onator semiconductor lasers and present near-field patterns and calculations of loss as a function of length, width, and lateral index step. We show that the periodicity of losses as a function of length is determined by a quantity analogous to the equivalent Fresnel number of macroscopic unstable resonators, which is determined by the lateral index step within the laser.

DOI:10.1049/ip-j.1987.0013

出版商:IEE    

年代:1987

数据来源: IET

摘要:

We review the technology involved in the fabrication of semiconductor lasers with non-planar mirrors. The symmetric unstable resonator semiconductor laser, in a planar (gain guided) configuration is shown to effectively suppress filamentation, and to emit a laterally coherent output up to approximately 350 mW. We show how the geometry of this laser can be changed slightly to produce different devices with improved output characteristics. As in the case of macroscopic resonators, the laser cavity can be designed in such a way that the output beam is optimised to certain specific applications.

DOI:10.1049/ip-j.1987.0014

出版商:IEE    

年代:1987

数据来源: IET

摘要:

In the present paper, the two-dimensional model of the heat spreading process in buried-heterostructure laser diodes is presented. We consider all heat sources in the structure. A main heat source is connected with nonradiative recombination and is located in the active region. In a lower part of the substrate and at a semiconductor/lower-contact interface, heat is produced by an absorption of the spontaneous radiation transferred from the active region through the passive layers. In all the layers, heat is generated by Joule heating. For every heat source, the electric analogue model of the heat-flux spreading process is used to define that part of its heat flux which is flowing along the diode axis and is reaching the heat sink directly through the stripe contact. It enables us to determine the approximate axial temperature distribution. This is achieved for the simplified one-dimensional heat flow by means of the Fourier series method. To reduce the nonlinear thermal-conduction equation to its linear form, the space transformation and the temperature transformation are used. The exact axial temperature distribution as well as the approximate temperature profiles in the centres of the layers are calculated by means of a self-consistent method using the above mentioned electric analogue model. In this calculation, the approximate axial temperature distribution is treated as the first approximation of the boundary condition.

DOI:10.1049/ip-j.1987.0015

出版商:IEE    

年代:1987

数据来源: IET

摘要:

We studied catastrophic optical damage of mounted GaAlAs/GaAs double-heterostructure (DH) laser diodes by measuring structure-parameter influence and by EL, CL, EBIC and TEM observation. Several lasing characteristics depend on the resonator length as well as near-field width and lasing wavelength. Their influence on the optical damage power was estimated and compared with measured data. The TEM observations showed a periodic trace of DL growth. The defect spacing decreases exponentially from the mirror into the active region. The defects are surrounded by a stress field causing an increase in absorption. Because the EL images of mounted laser diodes showed in most cases damage to the front facet, we measured the mechanical stress under operating conditions. The unsymmetrical mounting (at the edge of the submount) causes a higher stress at the front facet than at the rear facet.

DOI:10.1049/ip-j.1987.0016

出版商:IEE    

年代:1987

数据来源: IET