Directly modulated DFB laser on SiO2/Si substrate for datacenter networks

Shinji Matsuo, Takuro Fujii, Koichi Hasebe, Koji Takeda, Tomonari Sato, Takaaki Kakitsuka

Research output: Contribution to journalArticlepeer-review

39 Citations (Scopus)


Reducing the operating energy of a distributed feedback (DFB) laser is a critical issue if we are to use the device as a directly modulated light source employing wavelength division multiplexing technologies in short-distance datacom networks. A membrane buried heterostructure (BH) DFB laser on a SiO2 layer is one candidate for reducing the operating energy because it provides a strong carrier and optical confinement in the active region. For low-cost fabrication, we have proposed and developed a fabrication procedure that employs the buried growth of an InP layer by using a directly bonded InP-based active layer on a SiO2/Si substrate, which enables us to use a large-scale Si wafer. To overcome the problem of the difference between the thermal expansion coefficients of Si, SiO 2, and InP, we have used a thin active layer (∼250 nm) on a SiO2/Si substrate as a template for the epitaxial growth of a III-V compound semiconductor. A lateral current injection structure is essential for fabricating a device with a 250-nm-thick template. Our fabricated DFB laser with a 73-μm cavity length exhibits a threshold current of 0.9 mA for continuous operation at room temperature and achieves lasing at up to 100 °C. We have also demonstrated 171-fJ/bit operation with a 25.8-Gb/s NRZ signal. These results indicate that the BH DFB laser on a SiO2/Si substrate is highly suitable for use as a transmitter for datacom applications.

Original languageEnglish
Article number7001558
Pages (from-to)1217-1222
Number of pages6
JournalJournal of Lightwave Technology
Issue number6
Publication statusPublished - 2015 Mar 15
Externally publishedYes


  • DFB laser
  • lateral current injection
  • on-Si laser
  • optical interconnection

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics


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