Differences Between FOADM , ROADM and TOADM in WDM Networks?

differences between FOADM , ROADM and TOADM in WDM networks

– OADM is the most important part in the WDM architecture

– its used for wavelength routing and forwarding

– stands for optical add drop multiplexer

– it has 3 types :

1- FOADM

called fixed , it’s used to add and drop fixed predetermined wavelengths

configuration is depending on how boards are connected / fibered by site engineer

this configuration is static and need Manuel intervention to change the configuration

advantages : low cost and simplicity

2- ROADM

called reconfigurable, its used to add wavelengths to the same path ,, drop specific wavelengths fro the flow in to specific ports , pass through

it has the capability to dynamically selecting which wavelengths should be dropped or added

it’s based on WR ( wavelength router )

it contain tunable fiber grating modules and circulators to dynamically add / drop

you can dynamically change its configuration remotely , no need for site visit

advantages : flexibily , dynamic , software programmable

it’s main block called : wavelength selective switch ( WSS )

3- TOADM

called tunable , it’s similar to ROADM
but its based on whats called CWR

CWR ( colorless wavelength router ) which give the TOADM the ability to have colorless ports to be connected directly to the tunable OTs

OTs : optical transponders , so now we can connect the tunable transponders directly to the TOADM ( CLS ports ) for wavelengths routing and forwarding

CLS : colorless Ports

it has also port THRU , which can be used to connect 2 CWRs together to extend the number of degrees