AC-coupled burst-mode optical receivers employing mBnB line codes

Abstract

An AC-coupled burst-mode optical receiver employing mBnB line codes is proposed for optical multiple access networks. By introducing the spectral characteristics of mBnB, which is often used in optical communication systems, the proposed scheme utilizes AC-coupling in burst-mode receivers for the first time. The novel AC-coupled receiver removes DC-coupling so that it is free from the disadvantages of DC-coupled burst-mode receivers such as DC offset and external reset signal. Though DC-coupled burst-mode receivers require fast and expensive devices to realize quick signal threshold control, the AC-coupled burst-mode receiver can be implemented with low-cost devices for continuous mode operations. Moreover, this receiver is technically feasible because AC-coupled techniques are well established and many components are commercially available on the market. The proposed receiver can achieve fast response with minimum signal distortion by adjusting the cutoff frequency of AC-coupled circuit to the spectrum of mBnB. Using system models, the effects of AC-coupling on receiver performances are analyzed for several mBnB codes. The necessary properties of mBnB code to be employed in AC-coupled design are determined. In addition, a 1.25Gb/s experimental receiver is implemented with commercial ICs for gigabit Ethernet. Measured data are compared with the numerical results and good agreements are shown. Experimental results give a -27dBm sensitivity, a 21dB dynamic range, and a 74ns required guard time, which are well compatible with EPON burst-mode data link.