Mach-Zehnder interferometer with a uniform wavelength period.
We have realized a first optical filter composed of optical delay lines and couplers that has a periodic response with respect to wavelength, whereas a conventional optical filter is known to have a periodic response to relative optical frequency. This new filter can be constructed by using a phase-generating coupler (PGC) that supplies the optical delay lines with a wavelength-dependent nonlinear phase. The PGC, which is also composed of optical delay lines and couplers, can simultaneously provide a desired phase and an arbitrary amplitude coupling ratio. We applied our transformation method to a conventional Mach-Zehnder interferometer (MZI) as an example of an optical frequency filter and converted it to an optical wavelength filter. We fabricated the designed MZI on a silica-based planar lightwave circuit and successfully realized what is believed to be the first MZI with a uniform wavelength period.
NTT Photonics Laboratories, NTT Corporation, Atsugi, Kanagawa 243-0198, Japan. mizuno@aecl.ntt.co.jp
Takayuki
T
Mizuno
Tsutomu
T
Kitoh
Manabu
M
Oguma
Yasuyuki
Y
Inoue
Tomohiro
T
Shibata
Hiroshi
H
Takahashi