BEP 4253 4253 OPTICAL COMMUNICATION COMMUNICATION SYSTEM SYSTEM TUTORIAL 7
1.
An anal analog og opti optica call fi! fi!"" co# co##$ #$ni nicat catio ion n %&%t %&%t!# !# "!'$ "!'$i"! i"!%% an an SN( SN( of 4)*B 4)*B at t+! *!t!cto" ,it+ a po%t *!t!ction an*,i*t+ of 3)M-. Calc$lat! t+! #ini#$# optical po,!" "!'$i"!* at t+! *!t!cto" if it i% op!"ating at a ,a/!l!ngt+ of ).0# ,it+ a '$ant$# !ffici!nc& of ). 3.2*B#6
2.
A %il %ilic icon on pin pin p+o p+oto to*i *io* o*!! +a% +a% a '$a '$ant nt$# $# !ffic !ffici!n i!nc& c& of 75 75 at at a ,a/ ,a/!l !l!n !ngt gt+ + of ).8#. 9!t!"#in! : a6 t+! #!an #!an p+otoc$" p+otoc$""!nt "!nt ,+!n ,+!n t+! *!t!cto *!t!cto"" i% ill$#inat! ill$#inat!* * at a ,a/!l!ng ,a/!l!ngt+ t+ of ).8# ,it+ 5; of optical po,!". 6 T+! "#% '$ant$# noi%! c$""!nt in a po%t *!t!ction an*,i*t+ an*,i*t+ of 2)M- c6 T+! SN( SN( in *B ,+!n ,+!n t+! t+! #!an p+otoc$""! p+otoc$""!nt nt i% t+! t+! %ignal %ignal 2.)1A< 3.50nA< 55*B6
3.
T+! T+! p+o p+oto to*i *io* o*!! in P"o P"ol l!# !# 2 +a% +a% a cap capac acit itan anc! c! of of 8p= 8p=.. Cal Calc$ c$la lat! t!:: a6 t+! #ni#$# #ni#$# loa* "!%i%tanc! "!%i%tanc! co""!%pon co""!%pon*ing *ing to a po%t *!t!ction *!t!ction an*,i*t+ of 2)M- 6 t+! "#% t+!"#al noi%! c$""!nt in t+! ao/! "!%i%to" at a t!#p!"at$"! of 25>C c6 t+! SN( SN( in *B *B "!%$lting "!%$lting f"o# f"o# t+! t+! ill$#inatio ill$#ination n in P"ol!# P"ol!# 2 ,+!n t+! *a"? c$""!nt in t+! *!/ic! i% 1nA 004.@< 18.10nA< 30.3*B6
4.
T+! T+! p+o p+oto to*i *io* o*!! in in P"o P"ol l!# !# 2 an* an* P"o P"ol!# l!# 3 i% i% $%!* $%!* in a "!c! "!c!i/ i/!" !" ,+!" ,+!"!! it it *"i/!% an a#plifi!" ,it+ a noi%! fig$"! of 2*B an* an inp$t capacitanc! of p=. 9!t!"#in! : a6 t+! #ai#$# #ai#$# a#plif a#plifi!" i!" inp$t inp$t "!%i%tanc! "!%i%tanc! to #aintai #aintain n a po%t *!t!ction *!t!ction an*,i*t+ of 2)M- ,it+o$t ,it+o$t !'$aliation 6 t+! #ini#$# inci*!nt optical po,!" "!'$i"!* to gi/! an SN( SN( of 5)*B 1.13?@< 10.58;6
5.
A g!"# g!"#an ani$ i$# # p+o p+oto to*i *io* o*!! inc inco" o"po po"at "at!* !* into into an opti optica call fi fi!" !" "!c!i "!c!i/! /!"" ,o"?ing at a ,a/!l!ngt+ of 1.55# +a% a *a"? c$""!nt of 5))nA at t+! op!"ating t!#p!"at$"!. ;+!n t+! inci*!nt optical po,!" at t+i% ,a/!l!ngt+ i% 1)7; an* t+! "!%pon%i/it& of t+! *!/ic! i% ).7A;< %+ot noi%! *o#inat!% in t+! "!c!i/!". 9!t!"#in! t+! SN( in *B at t+! "!c!i/!" ,+!n t+! po%t *!t!ction an*,i*t+ i% 1))M-. 4).1*B6
7.
A %il %ilic icon on (AP9 (AP9 +a% +a% a '$a '$ant nt$# $# !ffi !ffici ci!n !nc& c& of 05 05 at at a ,a/ ,a/!l !l!n !ngt gt+ + of of ).3 ).0#< +a% an !c!%% a/alanc+! noi%! facto" of M an* a capacitanc! of 2p=. It #a& ! a%%$#!* t+at t+! po%t *!t!ction an*,i*t+ ,it+o$t !'$aliation6 i% 25M- an* t+at t+! *a"? c$""!nt in t+! *!/ic! i% n!gligil! at t+! op!"ating t!#p!"at$"! of 20). 9!t!"#in! t+! #ini#$# inci*!nt optical po,!" ,+ic+ can &i!l* an SN( of 23*B. 5).3*B#6
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BEP 4253 OPTICAL COMMUNICATION SYSTEM .
;it+ t+! *!/ic! an* con*ition% gi/!n in P"ol!# 7< calc$lat! : a6 t+! SN( otain!* ,+!n t+! a/alanc+! #$ltiplication facto" fo" t+! (AP9 fall% to +alf t+! opti#$# /al$! calc$lat!* 6 t+! inc"!a%!* optical po,!" n!c!%%a"& to "!%to"! t+! SN( to 23*B ,it+ MD).5Mop 14.2*B< 40.7*B#6
8.
A g!"#ani$# AP9 ,it+ D 1.)6 op!"at!% at a ,a/!l!ngt+ of 1.35# ,+!"! it% "!%pon%i/it& i% ).45A;. T+! *a"? c$""!nt i% 2))nA at t+! op!"ating t!#p!"at$"! of 25) an* t+! *!/ic! capacitanc! i% 3p=. 9!t!"#in! t+! #ai#$# po%%il! SN( ,+!n t+! inci*!nt optical po,!" i% 8 1); an* t+! po%t *!t!ction an*,i*t+ ,it+o$t !'$aliation i% 57)M-. 23.0*B6
0.
T+! p+oto*io*! in P"ol!# 8 *"i/!% an a#plifi!" ,it+ a noi%! fig$"! of 3*B an* an inp$t capacitanc! of 3p=. 9!t!"#in! t+! n!, #ai#$# SN( ,+!n t+!& a"! op!"at!* $n*!" t+! %a#! con*ition. 21.0*B6
1).
A pin p+oto*io*! op!"ating at a ,a/!l!ngt+ of ).83# +a% a '$ant$# !ffici!nc& of 5) an* a *a"? c$""!nt of ).5nA at a t!#p!"at$"! of 205. T+! *!/ic! i% $nia%!* $t loa*!* ,it+ a c$""!nt #o*! a#plifi!" ,it+ a 5)?@ f!!*ac? "!%i%to" an* an op!n loop gain of 32. T+! capacitanc! of t+! p+oto*io*! i% 1p= an* t+! inp$t capacitanc! of t+! a#plifi!" i% 7p=. 9!t!"#in! t+! inci*!nt optical po,!" "!'$i"!* to #aintain a SN( of 55*B ,+!n t+! po%t *!t!ction an*,i*t+ i% 1)M-. I% !'$aliation n!c!%%a"& 23.1*B#6
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