Abstract

Differential phase shift keying are today considered key solutions for the WDM long-haul transmission infrastructure, and a Mach-Zehnder interferometer (MZI) for its demodulation needs to have very low polarization dependent frequency shift (PDf). MZIs based on silica-based planar lightwave circuits can offer a compact reliable demodulator, but it suffers from a large PDf. In particular, they exhibit a large wavelength dependence on the PDf. It results in a narrow wavelength range where the PDf is sufficiently low, and this limits the operating range of the demodulator. In this paper, we propose a novel method for reducing the PDf over a wide wavelength range. We reveal that the large wavelength dependence of the PDf is due to both the polarization crosstalk of the half-wave plate and the birefringence of the waveguide. Using a mathematical approach, we derived a way to suppress the PDf by controlling the birefringence and the direction of the optic axis of the half-wave plate in the MZI. We confirmed the effectiveness of our proposed method experimentally and achieved a low PDF of $< 1\%$ for an FSR of over 140 nm in the wavelength.

© 2009 IEEE

PDF Article

References

You do not have subscription access to this journal. Citation lists with outbound citation links are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Cited By

You do not have subscription access to this journal. Cited by links are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription