Amplification Characteristics of Integrated Twin-Guide Laser Amplifier

Toshio KAMBAYASHI  Yasuharu SUEMATSU  

Publication
IEICE TRANSACTIONS (1976-1990)   Vol.E64   No.7   pp.489-496
Publication Date: 1981/07/25
Online ISSN: 
Print ISSN: 0000-0000
Type of Manuscript: PAPER
Category: Optical and Quantum Electronics
Keyword: 


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Summary: 
We propose a new type light amplifier composed of an integrated twin-guide (ITG) structure and discuss its amplification characteristics. It has two coupled guides: one is an active guide for the light amplification and the other is an output guide which is a loss-less passive guide for input and output of the light. Using a matrix method we derive two expressions of gain for transmission and reflection types of amplification. We obtain the regions of parameter in which the amplifier operates stably. The reflection type gain is usually larger than the transmission type one, because the path of the reflected light is longer than that of the transmitted light in the active guide. Although the amplifier has a resonator, the transmission type gain becomes insensitive to the wavelength of the amplified light under a certain condition. This feature is useful for the stable and wide-band amplification. We also discuss its noise characteristics by regarding only spontaneous emission as a noise sourse and express the signal to noise ratio and the noise temperature. The noise temperature is considered to be the temperature of a black body which emits the same amount of light as the spontaneous emission of the amplifier. As a result of numerical calculation, the temperature is estimated to be over a few 1000 K of a AlGaAs/GaAs laser amplifier, but the signal to noise ratio is expected to be 10-30 dB.