摘要:

The evolution of the fundamental modal field is considered as the normalised frequencyVis decreased in a ‘lower-outer-cladding’ doubly clad lightguide. In particular the paper examines the utility of the ‘infinite-cladding’ and ‘no-core’ approximations, and the application to slowly tapered finite-cladding fibres is mentioned.

DOI:10.1049/ip-j.1987.0017

出版商:IEE    

年代:1987

数据来源: IET

摘要:

A scalar two-dimensional analysis of a single-mode-fibre fused coupler is presented. Two theoretical models (one analytical and one numerical) are implemented and compared. The first model is based on the mode coupling in the central cross-section of the coupler, the second model employs the propagating-beam algorithm (PBA). Contrary to the analytical model, the PBA is suited to the analysis of the transition from guidance by the core to guidance by the cladding taking place in the tapers, including radiation loss. The influence of the external refractive index on the power transfer is investigated. The results obtained are in qualitative agreement with the experiments presented by Hillet al.

DOI:10.1049/ip-j.1987.0018

出版商:IEE    

年代:1987

数据来源: IET

摘要:

Measurements of the temperature dependence of the threshold current of InGaAsP/InP lasers are presented for compositions with wavelengths λ = 1.55 and 1.65 μm. 1.55 μm lasers have been investigated with either three or four epitaxial layers to study the influence of leakage currents. The experimental results are compared with theoretical investigations which are based on the assumption that Auger recombination is responsible for the temperature behaviour. The calculation of the Auger processes is reinvestigated. Fair agreement between experiment and theory demonstrates that Auger processes are the main cause for the temperature sensitivity of InGaAsP lasers.

DOI:10.1049/ip-j.1987.0019

出版商:IEE    

年代:1987

数据来源: IET

摘要:

Lateral waveguiding in the buried-stripe self-aligned laser is described. A channel etched in a current-confining layer provides a single vertical guide in the channel region and a coupled vertical guide outside the channel region. The lateral horizontal waveguide can be tailored to be real index guiding or real index antiguiding. This is achieved by choosing either the highest-order mode or the next highest-order mode as the one which couples best to the active layer in the coupled-guide system formed outside the channel.

DOI:10.1049/ip-j.1987.0021

出版商:IEE    

年代:1987

数据来源: IET

摘要:

The evolution of pulses in nonlinear single-mode fibres is investigated by means of direct numerical integration of the nonlinear Schrödinger equation and by numerical solution of the associated Zakharov-Shabat scattering equations. For pulses having an initial chirp, we identify and calculate critical values of the chirp. Loss in the fibre is shown to lead to extinction of the soliton character after a finite propagation distance. Phase noise in the initial pulse leads to a jitter in the pulse propagation time.

DOI:10.1049/ip-j.1987.0022

出版商:IEE    

年代:1987

数据来源: IET