Hitless errorless trimmable dynamic optical add/drop multiplexer devices
View Patent ↗The present invention is generally directed to integrated optical add/drop multiplexer devices in which light of a specific wavelength (or specific wavelengths) can be added to or dropped from a main fiber optic line. An actuation mechanism (e.g., heat) is used to tune and/or trim the devices. Some proposed architectures provide for tuning of the adding and dropping of channels in a hitless manner, a manner that is non-disruptive to other wavelength channels.
1. A hitless dynamic add/drop multiplexer comprising a continuously tunable reflective filter disposed within an optical waveguide segment, said optical waveguide segment having a first end and a second end, an optical circulator or optical coupler disposed at each end of said optical waveguide segment and optically coupled thereto, and at least one by-pass waveguide coupled to said waveguide segment by an optical switching means.
2. The optical signal processing device of claim 1 wherein said optical circulator or optical coupler is an optical circulator disposed at each said end of said waveguide segment and optically coupled thereto to form an optical circuit element.
3. The hitless dynamic add/drop multiplexer of claim 1 further comprising at least one phase shifter disposed to balance the phase difference between the signals in said optical waveguide segment and said by-pass waveguide.
4. The hitless dynamic add/drop multiplexer of claim 1 wherein said optical switching means is selected from the group consisting of Y-branch switches, X-junction switches, directional coupler switches, Mach-Zehnder switches, and multimode interference switches.
5. The hitless dynamic add/drop multiplexer of claim 1 further comprising a substrate upon which is disposed a plurality of components of said hitless dynamic add/drop multiplexers.
6. The hitless dynamic add/drop multiplexer of claim 1 further comprising a second said optical waveguide segment having a continuously tunable reflective filter disposed therewithin, and wherein said optical circulator or optical coupler is a two-port by two-port optical coupler disposed at each end of said two optical waveguide segments, two ports of each said optical coupler being respectively coupled to the first said end of each said waveguide segment and the second said end of each said waveguide segment.
7. The hitless dynamic add/drop multiplexer of claim 6 wherein said optical coupler is selected from the group consisting of directional couplers, multimode interference couplers, and Mach-Zehnder interferometers.
8. The hitless dynamic add/drop multiplexer of claim 6 wherein said optical coupler is tunable.
9. The hitless dynamic add/drop multiplexer of claim 2 or claim 6 further comprising a cross-bar switch and wherein at least two said circuit elements are connected by said cross-bar switch.
10. The optical signal processing device of claim 2 or claim 6 wherein at least two said circuit elements are disposed in parallel and further comprises polarization beam splitters disposed to send the two orthogonal polarizations of an incoming optical signal to the first end of each said waveguide segment as an input, and further comprise polarization beam combiners disposed to collect the two orthogonal polarizations at the second end of each said waveguide segment as an output.
11. The optical signal processing device of claim 2 or claim 6 further comprising a 1×2 switch whereof one port in said optical circulator or coupler disposed at said first end or ends of said waveguide segment or segments, employed as an input end, is connected to the input port of said 1×2 switch, and one port in the optical circulator or coupler disposed at said second end or ends of said waveguide segment or segments, employed as an output end, is connected to an output port of said 1×2 switch.