Low-cost multimode fiber Mach-Zehnder interferometer for differential phase demodulation

Yannick Keith Lize; Robert Gomma; Raman Kashyap

doi:10.1117/12.680098

24 August 2006 Low-cost multimode fiber Mach-Zehnder interferometer for differential phase demodulation

Yannick Keith Lize, Robert Gomma, Raman Kashyap

Proceedings Volume 6314, Photorefractive Fiber and Crystal Devices: Materials, Optical Properties, and Applications XII; 63140R (2006) https://doi.org/10.1117/12.680098
Event: SPIE Optics + Photonics, 2006, San Diego, California, United States

Abstract

Mach-Zehnder interferometers (MZIs) are used in many optical applications, such as measurement of the coherence length of a laser, thermal dynamic flow, flatness of plane optical plates, thickness of thin films, etc. In this type of interferometer, light passing through a sample region in one direction recombines with a second leg without traversing the sample twice. In telecommunication, MZIs are used for demodulating differential phase-shift-keyed (DPSK) signals. DSPK has attracted increased attention in fiber optic transmission in recent years because of its 3-dB optical signal to noise ratio improvement over standard intensity modulated transmission, as well as for its high tolerance to nonlinear effects and coherent crosstalk. In a standard fiber MZI, two wideband fiber couplers are spliced together with one arm providing a one-bit delay to convert the phase difference into an intensity modulation. In our alternate type of MZI, the two-mode interferometer, the time delay is obtained through the difference between the propagation constants of two modes instead of through a physical path length difference. We present here a novel single multimode fiber modal interferometer for DPSK demodulation. In this design, a second mode is excited by splicing a standard fiber to a multimode fiber length such that two modes beat together before recombining in a second splice. A numerical analysis and an experimental verification of the multimode fiber parameters to maximize the extinction ratio and minimize the length of the interferometer are presented. We investigate coupling, insertion losses, temperature sensitivity and polarization effects of using modes with and without radial symmetry. The design is extremely low-cost, easily manufactured and is intrinsically less temperature sensitive than standard MZI. Although balanced detection is lost, DPSK may still be advantageous because of its high tolerance to nonlinear effects and coherent crosstalk.

Citation Download Citation

Yannick Keith Lize, Robert Gomma, and Raman Kashyap "Low-cost multimode fiber Mach-Zehnder interferometer for differential phase demodulation", Proc. SPIE 6314, Photorefractive Fiber and Crystal Devices: Materials, Optical Properties, and Applications XII, 63140R (24 August 2006); https://doi.org/10.1117/12.680098

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available