\u00c0 son niveau le plus \u00e9l\u00e9mentaire, un syst\u00e8me de communication optique utilise un \u00e9metteur pour coder un message en un signal optique\u00a0; un canal, pour transporter ce signal vers une destination\u00a0; et un r\u00e9cepteur, pour redonner au signal sa forme originale et lisible.<\/p>\n\n\n\n
Un composant cl\u00e9 \u00e0 l'extr\u00e9mit\u00e9 r\u00e9ceptrice du syst\u00e8me est un dispositif capable de convertir l'\u00e9nergie lumineuse en un signal \u00e9lectrique. Ce dispositif, appel\u00e9 photodiode ou photod\u00e9tecteur, est con\u00e7u pour laisser passer le courant en pr\u00e9sence de lumi\u00e8re et pour emp\u00eacher le passage du courant en l'absence de lumi\u00e8re. Pour transformer ce courant en un signal utilisable, une configuration de circuit \u00e9lectrique commune est utilis\u00e9e : un amplificateur \u00e0 transimp\u00e9dance, ou TIA.\u00a0<\/p>\n\n\n\n
La configuration TIA comprend g\u00e9n\u00e9ralement un amplificateur op\u00e9rationnel (ampli-op), l'un des dispositifs les plus largement utilis\u00e9s dans la conception \u00e9lectronique. Un amplificateur op\u00e9rationnel est capable d'un gain \u00e9norme\u00a0: il peut prendre un signal d'entr\u00e9e minuscule et le transformer en un signal de sortie fortement amplifi\u00e9. Parce que le gain de l'ampli-op est si extr\u00eame, une r\u00e9sistance de r\u00e9troaction est int\u00e9gr\u00e9e \u00e0 la configuration. Cette configuration, comme le montre le sch\u00e9ma de droite, convertit efficacement un signal de courant de photodiode de bas niveau en une sortie de tension utilisable - entr\u00e9e de courant, sortie de tension.<\/p>\n\n\n\n
Th\u00e9oriquement parlant, c'est TIA en un mot. Pourtant, dans la pratique, il est difficile d'instaurer la stabilit\u00e9 dans le syst\u00e8me. Une approche standard consiste \u00e0 ajouter un condensateur de r\u00e9troaction \u00e0 travers la r\u00e9sistance de r\u00e9troaction afin de traiter le potentiel d'oscillation. C'est une strat\u00e9gie efficace, mais l'interactivit\u00e9 \u00e9troite entre les \u00e9l\u00e9ments du syst\u00e8me signifie que les modifications apport\u00e9es \u00e0 l'un peuvent avoir un impact significatif sur tous les autres. Cela se traduit par la n\u00e9cessit\u00e9 de prendre des d\u00e9cisions concernant les compromis acceptables dans le cadre de l'optimisation du circuit - les exemples incluent le gain souhait\u00e9, le niveau de bande passante \u00e0 atteindre et la quantit\u00e9 de bruit qui peut \u00eatre tol\u00e9r\u00e9e.<\/p>\n\n\n\n
De plus, \u00e9tant donn\u00e9 que le signal de photodiode typique est tr\u00e8s faible, il peut y avoir plusieurs \u00e9tages de transimp\u00e9dance dans le syst\u00e8me pour optimiser l'\u00e9quilibre entre le bruit et la bande passante. Si le premier \u00e9tage TIA donne un gain trop \u00e9lev\u00e9, la bande passante atteignable sera limit\u00e9e. Si le gain est trop faible, le rapport signal sur bruit (SNR) sera d\u00e9grad\u00e9.<\/p>\n\n\n\n
Il convient de noter que les TIA sont utilis\u00e9s dans un grand nombre d'applications au-del\u00e0 de la communication optique. En termes simples, ce sont des composants essentiels de tout syst\u00e8me qui mesure la lumi\u00e8re : lecteurs de disques compacts, \u00e9quipement de vision nocturne, t\u00e9l\u00e9commandes infrarouges et bien d'autres. Gr\u00e2ce \u00e0 une meilleure compr\u00e9hension des principes TIA et \u00e0 une exp\u00e9rience des d\u00e9fis TIA, les concepteurs de r\u00e9seau peuvent apporter de la polyvalence \u00e0 un large \u00e9ventail de t\u00e2ches.<\/p>","protected":false},"excerpt":{"rendered":"
At its most basic level, an optical communication system uses a transmitter to encode a message into an optical signal; a channel, to carry that signal to a destination; and a receiver, to turn the signal back into its original, readable form. A key component at the receiving end of the system is a device […]<\/p>\n","protected":false},"author":33,"featured_media":3338,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"content-type":"","site-sidebar-layout":"default","site-content-layout":"default","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"default","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[6,246],"tags":[],"class_list":["post-1485","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-blog","category-operational-technologies"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.precisionot.com\/fr\/wp-json\/wp\/v2\/posts\/1485","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.precisionot.com\/fr\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.precisionot.com\/fr\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.precisionot.com\/fr\/wp-json\/wp\/v2\/users\/33"}],"replies":[{"embeddable":true,"href":"https:\/\/www.precisionot.com\/fr\/wp-json\/wp\/v2\/comments?post=1485"}],"version-history":[{"count":0,"href":"https:\/\/www.precisionot.com\/fr\/wp-json\/wp\/v2\/posts\/1485\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.precisionot.com\/fr\/wp-json\/wp\/v2\/media\/3338"}],"wp:attachment":[{"href":"https:\/\/www.precisionot.com\/fr\/wp-json\/wp\/v2\/media?parent=1485"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.precisionot.com\/fr\/wp-json\/wp\/v2\/categories?post=1485"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.precisionot.com\/fr\/wp-json\/wp\/v2\/tags?post=1485"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}