摘要:

The paper reports on reliable high-power wide-bandwidth 1.3 μm trenched buried heterostructure (TBH) lasers grown by atmospheric MOVPE. The devices have bandwidths of up to 11 GHz and maintain excellent CW performance and long lifetimes. Data are presented for all of the above parameters, along with a discussion of the design considerations of the device structure.

DOI:10.1049/ip-j.1990.0002

出版商:IEE    

年代:1990

数据来源: IET

摘要:

The spectral index method is applied to both rib and strip-loaded directional couplers, both of which are widely used in optoelectronics. Analytical transcendental equations are constructed in terms of the polarised propagation constant β for the fundamental symmetric and antisymmetric modes. Excellent agreement with large scale mainframe programs is achieved for the calculated coupling lengths.

DOI:10.1049/ip-j.1990.0003

出版商:IEE    

年代:1990

数据来源: IET

摘要:

A large-signal dynamic travelling optical flux analysis of a GaAs/AlGaAs monolithic active integrated-optic waveguide (AIOW) is presented. The model uses a combination of numerical and analytical techniques to solve the photon flux and carrier density conservation equations in time, the longitudinal dimension and optical wavelength. An analysis of the fundamental and harmonic frequency response of the waveguide is obtained, along with pulse and sinusoidal modulation response. This analysis is compared with a small signal analysis of the guide, and the two models are found to be in extremely close agreement for the limiting case of a small signal input applied to the large signal model.

DOI:10.1049/ip-j.1990.0004

出版商:IEE    

年代:1990

数据来源: IET

摘要:

The spectral index method is a new and simple way of finding quickly and easily the guided modes and propagation constants of semiconductor rib waveguides. Here, the method itself is analysed, and its accuracy as compared with finite-difference results is confirmed. Even in its simplest form, the method produces accurate propagation constants andEorHfield profiles using little CPU time and negligible storage.

DOI:10.1049/ip-j.1990.0005

出版商:IEE    

年代:1990

数据来源: IET

摘要:

The concept of effective widths is shown to lead, in principle, to a theory for the upper lower version of the weighted index method. By applying the ‘method of moments’ to the scalar wave equation (quasi-TE mode), a basis is provided for procedures which previously relied on physical intuition. Numerical solutions are compared with the effective, weighted, upper lower and spectral index methods. The latter two methods agree well with a semi-vectorial finite difference method, and give good accuracy.

DOI:10.1049/ip-j.1990.0006

出版商:IEE    

年代:1990

数据来源: IET

摘要:

Nonlinear gain saturation is shown to result in a power dependence of the linewidth enhancement factor. This can explain a linewidth rebroadening or saturation at high power levels in semiconductor lasers, even if no side modes are considered.

DOI:10.1049/ip-j.1990.0007

出版商:IEE    

年代:1990

数据来源: IET

摘要:

We discuss the design of Mach-Zehnder wavelength duplexers for 1300 nm and 1530 nm band-centres using InGaAsP/InP strip-loaded waveguides. We show that this device has a high inherent tolerance to fabrication and waveguide parameter variation and is therefore particularly suitable for ‘dead-reckoned’ fabrication in a low-cost optoelectronic transceiver chip for local area fibre networks. Using a novel configuration of concentrically curved waveguides, crosstalk better than —11.75 dB has been achieved in both channels. The performance of the constituent waveguide bends and directional couplers is also discussed.

DOI:10.1049/ip-j.1990.0008

出版商:IEE    

年代:1990

数据来源: IET

摘要:

The buried-ridge stripe (BRS) laser has been modified for integration purposes. Adapting the laser to a quasi-planar configuration on the semi-insulating substrate, we report on an important improvement of the integrable BRS laser characteristics as compared with previously published ones. Also, the technology for this modified structure is shown to be compatible with the implanted transistor technology. No significant effect on the laser characteristics has been seen after Si implantation and subsequent heat treatment at 850°C for 10 s. A threshold current as low as 9.5 mA and an optical bandwidth of 6.1 GHz have been obtained in the case of Si implantation carried out after laser fabrication.

DOI:10.1049/ip-j.1990.0009

出版商:IEE    

年代:1990

数据来源: IET

摘要:

The paper describes the fundamental properties of the GaP-AlxGa1-xP heterostructure used for the semiconductor Raman laser and the low threshold operation of the buried heterostructure Raman laser, together with the first demonstration of lasing by a new structure having a layer with an intermediate refractive index for pump power introduction, which reduces the loss for the Stokes field. The paper also describes the important applications of the semiconductor Raman laser to optical-heterodyne demodulation, and frequency difference mixing for frequency-tunable far-inra-red generation, as one of essential tools for very wideband optical communication beyond 1 THz.

DOI:10.1049/ip-j.1990.0010

出版商:IEE    

年代:1990

数据来源: IET

摘要:

Current-controlled polarisation and wavelength switching in 1.3 μm GaInAsP ridge-waveguide twin-stripe (RWTS) lasers with a properly designed effective index profile is reported. In CW operation at room temperature, an output power of 4 mW can be switched from TM- to TE-polarisation with an extinction ratio of 15 dB by a control current of only 4 mA. The polarisation switching is accompanied by a wavelength shift of 17 nm. Under fast direct current modulation, intrinsic optical response times of less than 235 ps are obtained. A self-consistent analysis of the active lateral waveguide shows that the switching effect is based on the deformation of the TE-mode profile resulting from antiguiding controlled by a small injection current.

DOI:10.1049/ip-j.1990.0011

出版商:IEE    

年代:1990

数据来源: IET