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

Takaharu Ohyama, Akira Ohki, Kiyoto Takahata, Toshio Ito, Nobuhiro Nunoya, Hiroyasu Mawatari, Takeshi Fujisawa, Shigeru Kanazawa, Ryuzo Iga, Hiroaki Sanjoh

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)


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 x 1 multimode interference (MMI) optical coupler and a polarization beam combiner for wavelength multiplexing. The TOSA is 8.7 mm x 28.7 mm x 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 x 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.

Original languageEnglish
Article number7050237
Pages (from-to)1985-1992
Number of pages8
JournalJournal of Lightwave Technology
Issue number10
Publication statusPublished - 2015 May 15
Externally publishedYes


  • 100 Gbit/s Ethernet
  • Distributed feedback laser
  • electro-absorption modulator
  • polarization
  • transmitter
  • transmitter optical subassembly (TOSA)

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics


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