Optical fiber communication -62021/2/19 F-P( Fabry-Pery)腔型光滤波器:解复用 A:工作原理多光束干涉有频率选择物性 At,= Anrt At,=Arri t2 At= anr t At,= Att 当r1r2反射率较高时必须考虑每光束干涉
1-6 Copyright Wang Yan 2021/2/19 Optical fiber communications 一、F-P(Fabry-Pery)腔型光滤波器：解复用 A:工作原理多光束干涉有频率选择物性 2 3 1 3 4 2 At = Ar r t 2 2 1 2 3 2 At = Ar r t 2 2 1 2 At = Ar r t 1 2 1 At = At t − A = A 1 t 1 r 2 t 2 r 当r1 r2反射率较高时必须考虑每光束干涉
Optical fiber communication 72021/2/19 每一束透射波比前一束在相径上延迟Φ=k2=4Tn/A0=4Tnf/c 而振幅减小须乘以因子r1r2。令 则:b=exP(=/ At1=A12exp(一j中) At2=At t, exp(- rri exp(一少小)t2=A1h At= At,h
1-7 Copyright Wang Yan 2021/2/19 Optical fiber communications 每一束透射波比前一束在相径上延迟Φ＝k2l=4πnl/λ0=4πnlf/c 而振幅减小须乘以因子r1 r2 。令 exp( ) h = r1 r2 − j 则： exp( ) At1 = A1 t 1 t 2 − j At2 = A1 t 1 t 2 exp(− j)r2 r1 exp(− j)t 2 = At1 h = 2 At3 At1 h
Optical fiber communication 82021/2/19 透射光的复振幅为歌词透射光的叠加 At= At,+ At +at+ t t At1(1+h+h2+…)= 4(t exp(jo) 1-h1-h 着:r1=r2=rt1=t2=t(振幅 功率:R=r2,T=t2无损耗情况下R+T=1 Tt= A T exp(一j) 1-Re apCo) exp(jD)=1
1-8 Copyright Wang Yan 2021/2/19 Optical fiber communications 透射光的复振幅为歌词透射光的叠加 ( j) h At t h A t At h h At At At At − − = − = + + + = = + + + exp 1 1 ( ) (1 ) 2 1 2 1 1 2 3 若：r1=r2=r t1=t2=t (振幅) 功率：R=r2 , T=t2 无损耗情况下 R＋T＝1 1 Re ( ) exp( ) x p j AT j Tt i − − − = exp(− j) =1
Optical fiber communication 92021/2/19 输出光强: l= KAtAt Ka.AT 1-Re xp(jo) (1-R)2+4Rsm2如 2 K为常数:L=KA(入射光波的光强 B)FP腔的功率传输系数( Fabry Perot Transfer Fuction) 1+[4R/(1-R)/sm2p 1+(2F/x)2sin2(2m/c)
1-9 Copyright Wang Yan 2021/2/19 Optical fiber communications 输出光强： ( ) 2 Re (1 ) 4 sin 1 2 2 2 2 R R I T x p j KA A T I KAtAt i i i t − + = − − = = K为常数： 为入射光波的光强 B )F—P腔的功率传输系数(Fabry Perot Transfer Fuction) I = KAtAt i ( F ) ( nlf c) R R I I i t 1 2 / sin 2 / 1 2 1 [4 /(1 ) ]sin 1 2 2 2 2 + = + − = =
Optical fiber communication 02021/2/19 Where F=z√R/(-R)f cg an Ca 谐振频率:m-=2123,… 谐振波长: 2nl maX 传输系数的最大值: m1+(2F/r)21+[4R/1-R)
1-10 Copyright Wang Yan 2021/2/19 Optical fiber communications Where F = R /(1− R) nl cq f 2 = f 谐振频率： q=1,2,3,…… 谐振波长： 传输系数的最大值： nl cq f oq 2 = q nl oq 2 = max =1 1 [4 /(1 ) ] 1 1 (2 / ) 1 min 2 2 F + R − R = + =