Contents I. Introduction
The current communication network confronts tremendous challenge resulting from the integration of the three networks (the telecommunication network, the internet and the broadcast television network), the replacement of copper cables with optical fiber cables and the emergence of new media (IPTV, HDTV, 3D, multicast, triple-play, etc.) and new applications (the grid computing, the cloud computing, the big data, the video surveillance and the internet of things) [1]. The technologies and applications of optical communications and networks have been developing rapidly under the pushing of increasing demand. The transmission rates of optical fiber communication in the backbone network have evolved into high speed and ultrahigh speed such as 2.5Gb/s, 10Gb/s, 40Gb/s, 100Gb/s and etc. In the metropolitan area network (MAN) and local area or access network (LAN or AN), the communication system and data rate are presenting the diversity including SONET, SDH and Ethernet, which is various in different countries and regions. In addition, the optical network is evolved towards the intelligent network such as Automatically Switch Optical Networks (ASON) and Software Defined Optical Networks (SDON) in order to support applications and requirements mentioned above. The optical networks should be able to realize the dynamic cross-connect and add/drop multiplexing as well as the variable bandwidth, the multicast and the broadcast, the traffic convergence and grooming, the integration between the optical layer and electrical layer, and the power-efficient. Therefore, it is required that the digital optical transceiver modules should be transparent for different data-rates, i.e., they can adaptively support multi-rates like SONET, SDH and the optical access network. Unfortunately, the current commercial off-the-shelf digital-optical-receiver is of a fixed rate or an adjustable rate within a very narrow range [4], [5]. To our knowledge, a broadband digital optical receiver that supports different communication systems and multi-rates has not been seen. In this paper, an adaptive-generalized digital-optical-receiver-module with multi-rates from 100Mb/s to 10.709Gb/s, is developed by using the broadband photodetector, the limiting amplifier, and the multi-rate CDR circuits, and then the integration of optical transceiver module is achieved combining it with the transmitter part. This module will be widely used because of supporting the clock recovery and data regeneration with multi-rates in SONET and SDH standards, as well as EPON and GPON like 100M or Gigabit Ethernet.
