Improvement of oscillation characteristics of ring oscillator through photoconductivity and dielectric constant of photo
- PDF / 784,109 Bytes
- 8 Pages / 595.276 x 790.866 pts Page_size
- 74 Downloads / 185 Views
ORIGINAL PAPER
Improvement of oscillation characteristics of ring oscillator through photoconductivity and dielectric constant of photorefractive materials M K Maurya* Department of Physics, Rajeev Gandhi Government P.G. College, Ambikapur, Chhattisgarh 497001, India Received: 09 May 2019 / Accepted: 06 September 2019
Abstract: The intensity of oscillation and the oscillation frequency shift are two most important parameters that characterize the performance of a photorefractive ring oscillator. In this paper, the effect of photoconductivity and dielectric constant of photorefractive (PR) materials on these parameters has been studied in case of non-degenerate two-wave mixing in PR materials. It has been found that for a given value of photoconductivity of PR material, the highly reflecting (R [ 90%) cavity mirrors are much effective parameter as compared to the other parameters (frequency detuning, absorption strength, energy beam coupling strength and dielectric constant) for the enhancement of the intensity of oscillation in the oscillator. Also, the magnitude of oscillation frequency of the photorefractive ring oscillator (PRO) can be increased by inserting PR crystal of lower dielectric constant (e\7:0), higher photoconductivity DC (rp [ 500 pS/cm) and highly reflectivity (R [ 90%) cavity mirrors provided that the cavity-length detuning p [ 1:0 of the oscillator is higher. This means that the intensity and frequency of the PRO could be controlled by the dielectric constant and photoconductivity of a PR crystal which would greatly improve performance of a PRO and their applications based on these photorefractive ring oscillators such as wave front color conversion, optical limiting, optical computing and beam cleanup. Keywords: Ring oscillator; Photoconductivity; Dielectric constant of the photorefractive materials PACS Nos.: 42.50.-p; 42.65.Hw; 42.65-k
1. Introduction Photorefractive effects have been extensively studied during the last decades because of their strength and diversity and also because of a large application potential [1]. These effects are present in many materials, including ferroelectric, semi-conductive crystals and polymers [2–5]. Photorefractive media provide a promising candidate for information systems because of their unique properties, such as low intensity operation, massive storage capacity, directional energy transfer, real-time response and large dynamic range [1–7]. These features make them attractive materials for fiber optic devices such as modulators, switches, dispersion compensators, filters, photorefractive oscillators and wavelength division multiplexers/demultiplexers [1–25]. Photorefractive ring oscillator (PRO) containing photorefractive crystals has proven their utility in the
construction and operation of various photorefractive circuits [12–30]. Two interconnected rings with two-wave mixing crystals have been used to display an optical analog of flip-flop circuit [1, 30]. A four-wave mixing crystal can be considered as an eight-pin optical processor [1, 30]. Fa
Data Loading...
