Browse Prior Art Database

Modulator Using Resonant Coupling

IP.com Disclosure Number: IPCOM000096103D
Original Publication Date: 1964-Dec-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 29K

Publishing Venue

IBM

Related People

Okaya, A: AUTHOR [+2]

Abstract

Drawing B depicts a technique for inducing greater changes in the absorption coefficient of a crystal modulator for a given crystal energy density P. The Franz-Keldysh effect teaches that the absorption coefficient of certain types of crystals can be varied by establishing a sufficiently large potential gradient E(o)/L in the crystal. Depending on the method selected for establishing the electric field, the energy density P necessary to provide the requisite gradient E(o)/L varies.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 80% of the total text.

Page 1 of 2

Modulator Using Resonant Coupling

Drawing B depicts a technique for inducing greater changes in the absorption coefficient of a crystal modulator for a given crystal energy density P. The Franz-Keldysh effect teaches that the absorption coefficient of certain types of crystals can be varied by establishing a sufficiently large potential gradient E(o)/L in the crystal. Depending on the method selected for establishing the electric field, the energy density P necessary to provide the requisite gradient E(o)/L varies.

Drawing A shows the conventional modulator arrangement comprising a crystal of length L connected to a DC power source. The latter is of sufficient capability so as to produce the gradient E(o)/L necessary for observing the Franz-Keldysh effect. The energy density P(dc) required to establish the desired gradient is given by the relationship P(dc) = epsilon E(o)/2//2.

Drawing B depicts the technique for producing the electric field. An AC power source is coupled to the crystal by resonance, i.e., by placing the crystal in a resonant cavity and setting up a standing wave in it. The effect is to establish within the crystal separate regions having the requisite gradient E(o)/L. The energy density P(ac) required to establish the desired gradient E(o)/L is given by the relationship P(ac) = epsilon E(o)/2//16. The number of regions, and hence, the energy density required can be varied by varying the frequency of either the AC source or the dimensions of the...