Flip-chip interconnection EA-DFB laser module for 100-Gbit/s/λ application

We have developed a flip-chip interconnection technique to solve the problem of the degradation of the modulation bandwidth of an optical transmitter due to the parasitic inductance of bonding wire. And we have fabricated an LE-EA-DFB laser module that has a 3-dB bandwidth of 59 GHz thanks to our flip-chip interconnection technique. The fabricated optical receiver, which includes a wideband electrical amplifier, has a 3-dB bandwidth of 51 GHz. Using these optical modules with a 3-dB bandwidth of more than 50 GHz, we have obtained a bit-error rate of less than 2 × 10⁻⁴, which is an error-free condition using KP4 forward error correction, under 53.2-Gbaud 4-level pulse amplitude modulation (4-PAM) operation without an equalizer even after a 2-km transmission through single-mode fiber.

I. Introduction

Internet traffic has been increasing greatly owing to the rapid growth of cloud computing and mobile services. The Ethernet data rate continues to increase in order to handle the huge amount of data. 100-gigabit Ethernet (100GbE) was standardized in 2010 [1] and an IEEE task force is undertaking the standardization of 400-gigabit Ethernet (400GbE) [2]. For long-reach applications (such as 10- and 40-km single-mode fiber (SMF) transmission), 100GbE standards use a multi-lane interface with a data rate of . And an scheme is a promising candidate for long-reach . As mentioned above, recent Ethernet standards tend to employ a multi-lane interface. However, a smaller number of lanes is desirable in terms of reducing the power consumption and size of a transceiver. Therefore, a operation optical transmitter will be needed in the near future.