Transmitter Optical Subassembly Using a Polarization Beam Combiner for 100 Gbit/s Ethernet over 40-km Transmission

• Published in: Journal of lightwave technology Vol. 33; no. 10; pp. 1985 - 1992
• Main Authors: Ohyama, Takaharu, Ohki, Akira, Takahata, Kiyoto, Ito, Toshio, Nunoya, Nobuhiro, Mawatari, Hiroyasu, Fujisawa, Takeshi, Kanazawa, Shigeru, Iga, Ryuzo, Sanjoh, Hiroaki
• Format: Journal Article
• Language: English
• Published: New York IEEE 15-05-2015; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: 100Gbit/s Ethernet; Adaptive optics; Arrays; distributed feedback laser; electro-absorption modulator; Laser beams; Optical coupling; Optical device fabrication; Optical filters; Optical polarization; polarization; TOSA; transmitter; transmitter optical subassembly (TOSA); polarization; 100 Gbit/s Ethernet; Distributed feedback laser; electro-absorption modulator; transmitter
• ISSN: 0733-8724; 1558-2213
• DOI: 10.1109/JLT.2015.2402676

A transmitter optical subassembly (TOSA) has been developed for a 100-Gbit/s Ethernet system for a long optical transmission distance over a 40-km single-mode fiber (SMF). To obtain a high optical output power and a high dynamic extinction ratio, the TOSA consists of two two-channel distributed feedback laser diode array chips integrated with electro-absorption modulators (EADFB laser array chips) with a 2 × 1 multimode interference (MMI) optical coupler and a polarization beam combiner for wavelength multiplexing. The TOSA is 8.7 mm × 28.7 mm × 6.5 mm including an LC-type receptacle. The TOSA has a twin collimator path for two EADFB laser array chips. The wavelength multiplexer consists of a mirror, a half-wavelength plate, and a polarization beam combiner. The TOSA could improve the optical output power by around 2 dB compared with a TOSA with a four-channel EADFB laser array chip and a 4 × 1 MMI optical coupler. An optical modulation amplitude of over 0.5 dBm and a mask margin exceeding 21% were obtained for each lane when all lanes were operated simultaneously with an EA modulator driving voltage of 1.5 V at a bit rate of 25.78125 Gbit/s, which fully satisfies the 100GBASE-ER4 specifications. We demonstrated error-free operation for an SMF transmission of over 40 km. Moreover, we confirmed that the TOSA was capable of error-free SMF transmission over 60 km with a power penalty of less than 1.4 dB.