摘要:

High-speed switching matrices for wide-band synchronous data are difficult to fabricate using purely optical or electronic techniques. A new approach is proposed with electronic logic and intimate optical interconnection to exploit the best features of each technology.

DOI:10.1049/ip-j.1987.0044

出版商:IEE    

年代:1987

数据来源: IET

摘要:

A complete process is described whereby on-chip mirrors may be fabricated in Ti : LiNbO3stripe waveguide devices using micro-focal ion-beam machining. Experimental results are presented for a device operating at 1.523 μm wavelength, TM mode. An interferometric technique is used to distinguish the reflection from the on-chip mirror from other spurious reflections. Approximately 24% power reflectivity is observed. Results are compared with a simple theoretical model of the chip response under different conditions, and good agreement is obtained.

DOI:10.1049/ip-j.1987.0045

出版商:IEE    

年代:1987

数据来源: IET

摘要:

A scalar-field integral equation is employed to find the propagation characteristics of guided modes of an inhomogeneous optical fibre of arbitrary transverse shape. Two facts make the proposed method quite efficient. First, by employing the scalar-field integral equation, the propagation problem is reduced to a standard eigenvalue problem, where thelower-ordermodes correspond to thelargereigenvalues. Hence, the eigenproblem can be manipulated efficiently by variants of the power method. Further, the major computation in the associated power method can be arranged into the form of a convolution, which in turn can be performed using the fast Fourier transform (FFT).

DOI:10.1049/ip-j.1987.0046

出版商:IEE    

年代:1987

数据来源: IET

摘要:

A versatile semiconductor laser model has been developed by the addition of a frequency-dependent gain model to the transmission-line modelling (TLM) method. The model provides a sampled optical output waveform for a modulated laser, from which output spectra may be found. To minimise computing time, a technique of sampling below the optical frequency is introduced. The theoretical basis for this model is considered, and the results gained for a 300 μm cavity heterojunction laser are compared with those given by the solution of the rate equations.

DOI:10.1049/ip-j.1987.0047

出版商:IEE    

年代:1987

数据来源: IET

摘要:

In the paper a fibre-optic sensor which can be used to measure temperature continuously over the range 300–1100 K is described and its characteristic is reported. The measurement of the ‘decay time’ of fluorescence of Nd-doped glass and garnet is used as the means of determining temperature with a solid-state optoelectronic sensor system.

DOI:10.1049/ip-j.1987.0048

出版商:IEE    

年代:1987

数据来源: IET

摘要:

The paper analyses optical bistability in semiconductor lasers using a simple circuit model to represent the laser and cavity. It is believed that this type of model makes laser analysis readily accessible to electronic engineers and that the associated circuit concepts lead to new insights and techniques. The model is developed from a simple LCR circuit with nonlinearity introduced through the charge dependence of the components. The model is justified through a detailed comparison of the results with those of other workers.

DOI:10.1049/ip-j.1987.0049

出版商:IEE    

年代:1987

数据来源: IET

摘要:

We present an approximate but comprehensive theoretical model for heterodyne ASK receivers relevant to optical communication systems where the transmitter and local oscillator have significant linewidths. The ASK receiver modelled here uses square-law detection and post-detection filtering. As a consequence of this detection scheme a key issue in the theory is to account for the very different noise statistics associated with receiving ONE and ZERO symbols. The theory also takes into account receiver noise and nonideal intermediate frequency (IF) filter characteristics and permits an evaluation of optimum threshold setting. Detailed numerical results for receiver sensitivity for a typical 140 Mbit/spin-FET front end are presented. The receiver sensitivity penalty for nonzero linewidth is found to be less than 2.3 dB for IF linewidth below the very large value of 0.5 of the bit rate for an optimum ASK receiver. This clearly indicates the advantage of postdetection filtering in coherent optical receivers using rather broad linewidth lasers compared with the system considered earlier where the noise filtering was performed at the IF stage.

DOI:10.1049/ip-j.1987.0050

出版商:IEE    

年代:1987

数据来源: IET