An equivalent lumped element electric circuit model for traveling wave semiconductor laser amplifier has been developed using the rate equation for carriers, SPICE simulation of the circuits gives results in close agreement with the experimental data and values from sophisticated analyses. The modulation bandwidth and transient response were examined by including parasitic elements in the intrinsic model. © 2007 Wiley Periodicals. Inc.

ABHIRUP BARMAN

Radio Physics and Electronics

I SENGUPTA

P K BASU

University of Calcutta (informally known as Calcutta University or CU) is a collegiate public state university located in Kolkata, West Bengal, India.&nbsp;Within India it is recognized as a &quot;Five-Star University&quot; and accredited &quot;A&quot; Grade by National Assessment and Accreditation Council.

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The University of Calcutta has secured the Fifth position among the Universities of India in the prestigious &quot;Indian University Ranking 2019&quot; list, released by the NIRF of the Ministry of Human Resource Development, Government of India.

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It was established on 24 January 1857, and was one of the first institutions in Asia to be established as a multidisciplinary and Western-style university. Its alumni and faculty include several heads of state, heads of government, social reformers, prominent artists, only academy award winner and Dirac medal winner in India, many Fellows of the Royal Society and five Nobel laureates as of 2019 which is highest in South Asia.

University Of Calcutta

Microwave and Optical Technology Letters

An equivalent circuit model of uni-traveling carrier photodiode (UTC-PD) is developed from integral carrier density rate equation and few important properties of the device such as the electrical and optical characteristics are evaluated by employing advanced device physics. Circuit model incorporates chip and package parasitic of the device quite simply to provide practical behaviour of UTC-PD. We have developed small signal ac circuit model which is useful for the analysis of low power modulation characteristics of the device and dc circuit model which is advantageous to find wavelength dependent responsivity fairly accurately. At high optical input power the device bandwidth is found to be increased through enhancement of self-induced field in the absorption region and high output power can be derived from the device when absorption width is large. Such condition calls for large signal analysis. We have developed large signal circuit model by combining few mathematical transformations with small signal circuit model with different circuit element values. Our large signal model is unique that the same circuit can be used for both small and large signal analysis. With large signal model the optical power induced bandwidth improvement and output photocurrent saturation are explained. Large signal model is validated through linearity and IP3 analysis which found close agreement with the measured results. © 2017, Springer Science+Business Media, LLC.

Optical and Quantum Electronics

Small and large signal analysis using circuit model of InGaAs/InP based uni-travel carrier photodiode

This paper presents an equivalent lumped element electric circuit model for traveling wave semiconductor optical amplifier (SOA) in integrated circuit applications. The model facilitates incorporation of chip and package parasitic elements of SOA. The model is used to represent an all optical 2 × 2 switch based on cross gain modulation in SOA capable of operating at an ultra fast speed. SPICE simulation of the switch with the proposed circuit model provides bit error rate (BER) values at the switch output which agrees well with the experimentally measured values at 10 Gb/s. The degradation of switching performance has been examined in terms of bit error rate, modulation bandwidth and switching time in the presence of chip parasitic elements of SOA. © 2010 Springer Science+Business Media, LLC.

Circuit model for analysis of SOA-based photonic switch

Semiconductor Optical Amplifiers (SOA) are key components in the present day all optical networks. They are used as wavelength converters, optical logic gates, bit comparators and many other all-optical digital signal processing applications. To design the systems, fast and efficient models need be developed considering the basic physics of the SOA. In the present paper, we describe two models that are useful in explaining the high frequency and transient behaviour of SOAs. In the first one, developed by us, the rate equations for photons and carriers in a TW-SOA are suitably tailored so that physical quantities can be replaced by circuit elements like resistors and capacitors and current sources. The equivalent circuit can then be analysed by SPICE simulation. Parasitic elements can easily be included in the model. Satisfactory agreement with available experimental data and results with rigorous transfer matrix method has been obtained. The second model, the reservoir model, developed by Mathlouthi et al based on wideband steady state Connelly model, is useful for predicting the transient and high frequency behavior of SOA-based gates. In our work the reservoir model has been applied to explain the cross gain modulation and gain transient effects for single and WDM signals. It works quite fast to describe the behaviour of long cascades of SOAs. The simulated results agree closely with the experimental results for 1 Gb/s bit stream applied to single and cascaded SOAs and also in WDM systems. © 2007 IEEE.

Proceedings of the 14th International Workshop on the Physics of Semiconductor Devices, IWPSD

SPICE and reservoir models for Semiconductor Optical Amplifiers for high speed optical signal processing

The electrical equivalent circuits of quantum cascade lasers (QCLs) under steady state and under an ac small-signal are developed by employing simplified rate equations for electronic transitions between two levels and the rate equation for photon numbers. Two interactive circuits represent the steady state behaviour and another two coupled circuits model the ac small-signal performance of a QCL. The equivalent circuits are then used for SPICE simulation. The steady state equivalent circuit reproduces the light current curve of QCLs. The ac equivalent circuit yields the intensity modulation response, which matches almost exactly with the curve obtained from reported numerical calculations based on a third-order system model. In addition, the ac model is employed for SPICE simulation to give values of the modulation bandwidth for different values of photon lifetime. The SPICE model gives a slightly different curve for the bandwidth against photon lifetime from the curve plotted using the approximate analytical expression. © IOP Publishing Ltd.

Journal	Data powered by TypesetMicrowave and Optical Technology Letters
Publisher	Data powered by TypesetWILEY-BLACKWELL
ISSN	0895-2477