Dynamic Analysis of a Fibre-Optic Ring Resonator Excited by a Sinewave-Modulated Laser Diode

Abstract

This article describes a theoretical dynamic analysis of a fibre-optic ring resonator (FORR) when excited by a sinusoidally-modulated laser diode (LD). The results are given for different conditions of the resonator, namely, modulating frequency, amplitude modulation index, power coupling coefficient of coupler, loop delay time τ and the phase angle between FM and AM response of the LD. When the modulation frequency f m exceeds a limiting value, such that f mτ is greater than about 0.0002, the output response deviates from steady state and exhibits an oscillatory behaviour with overshoots. Also, when the value of f mτ becomes greater than one, the response does not show any resonance in the ring and the output approximates to the intensity modulation of the LD. An unknown FM characteristic of a given LD can be determined from the ring resonator response.

Characteristics of tuneable optical filters using optical ring resonator with PCF resonance loop

“…By comparing Figures 2 and 3, we observe that the effect of Λ values on the ORR transmission is more than that of d/Λ variations. In general, with an input of a sinewave-modulated laser signal E in (t) with an angular modulation frequency of ω m , the filtering characteristics of the ORR in Figure 1, after n number of field circulations in the resonator loop, can be expressed as (see Equation (2)) [24].…”

“…In last two decades, optical ring resonators (ORR) with different configurations, based on fiber and wave-guides [1][2][3][4], have been analyzed for different applications such as polarization sensing [5], bio-sensing [6], optical filters [7][8][9], dispersion compensation [10,11], optical triggering and optical integration/differentiation [2], optical bistability [12,13], add/drop multiplexer [14], optical switching [15][16][17][18], and various other applications [19][20][21]. In the early works, steady state [2,22] and dynamic responses of ORR built on fiber were analyzed [23,24] for applications in polarization sensing [7], FM deviation measurement of a laser diode (LD) [24], optical triggering, optical integration/differentiation and fiber dispersion compensation [2], and rotation sensing [22]. Recently, dynamic resonance characteristic of fiber ring resonator has been analyzed for gyro systems [25].…”

“…Generally, the characteristics of ORR based optical filters are determined by their frequency responses which in turn depends on the characteristic parameters of the ORR. The characteristic parameters of an ORR, that influence filter response, are resonator loop length, coupling coefficient of the coupler, transmission parameters of the loop fiber, and modulation frequency of the circulating field intensity in the resonator [23,24].…”

“…In accordance with developed theory of the ORR [27], the objective of this study is to present an analysis of tuneability of optical filter using an optical ring resonator when excited by a sinewave-modulated laser diode. Baed on previous ORR structures [23,24], where singlemode fiber (SMF) used as the resonator loop, in this paper, we assume to use a PCF resonance loop built on a PCF coupler [28,29]. The peculiar properties of PCFs have interesting effects on transmission function of the ORR.…”

“…To quantify the influence of the characteristic parameters of the loop PCF on the characteristic response of the ORR, the ORR loop transmission is analyzed by using the formulation developed by Pandian et al [24] and Seraji et al [23]. The novelty of the PCF-based ORR compared with SMF-based ORR is that the tuneability of response of the former is opened to more characteristic parameters and can be more compact due to shorter length of the loop.…”