The success of optical technology has introduced a new future for the Internet. With the many advantages of optical technology, multimedia applications which require strict quality of service(QoS) are able to be guaranteed in an optical network. Unfortunately, the optical technology still have some limits in setting up a connection. One of these limits is that a lightpath must use the same wavelength on all the links along its path from source to destination in an optical network without wavelength converters. This limit influents the resource utilization. In an optical network, wavelength converters are used to overcome this limit so they will help to improve the efficiency of the resource utilization. However, because of their expensiveness, a limited number of wavelength converters are usually used at some routers in optical networks. Many researchers have been working on multi-domain routing protocol for optical networks. In this thesis, we will implement and evaluate the performance of three optical inter-domain protocols in an optical network with wavelength converters. In particular three protocols which are discussed in dept are: Optical Border Gateway Protocol (OBGP), Optical Border Gateway Protocol Plus (OBGP+) and IDRA-based Routing Protocol (IDRA protocol). By building the simulations for each protocol in OPNET, we compare the performance of the three protocols based on two metrics: the blocking ratio of inter-domain lightpath requests and the overall number of routing messages to archive this blocking ratio. Moreover, we also evaluate the efficiency of wavelength converters in an optical network.