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US 8,275,224 B2Granted
Coherent receiver having an interleave-chirped arrayed waveguide grating
AssigneeAlcatel Lucent
InventorChristopher R. Doerr
Life of this patent
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Abstract
An optical coherent detector that employs an interleave-chirped arrayed waveguide grating (AWG). The AWG has a periodic chirp pattern that enables the AWG to function as an optical 90-degree hybrid. If the AWG is implemented using a birefringent material, then the AWG can also function as a polarization demultiplexer. In one embodiment, the AWG is designed to simultaneously function as a wavelength demultiplexer, a polarization demultiplexer for each wavelength-division-multiplexed (WDM) signal component, and a 90-degree hybrid for each polarization-division-multiplexed component of each WDM signal component.
Claims21
An apparatus, comprising an arrayed waveguide grating (AWG) that comprises:
- a substrate having a planar surface;
- a first optical star coupler being along said surface and having first and second optical inputs and a first spatial array of optical outputs;
- a second optical star coupler being along said surface and having a second spatial array of optical inputs and a third spatial array of optical outputs;
- and
- an array of waveguide arms, each waveguide arm connecting one optical output of the first spatial array to a corresponding optical input of the second spatial array, wherein the array of waveguide arms is configured to cause a first set of four optical outputs of the third spatial array to receive four different phase combinations of light received at the first and second optical inputs in response to the light received at the first and second optical inputs being of about the same wavelength, wherein the four different phase combinations are combinations of the light from the first and second optical input ports with relative phases of about 0, π/2 radians, π radians, and 3π/2 radians.
2 more elements
A method of processing an optical signal, comprising:
- (a) providing an arrayed waveguide grating (AWG) comprising:
- a substrate having a planar surface;
- a first optical star coupler being along said surface and having first and second optical inputs and a first spatial array of optical outputs;
- a second optical star coupler being along said surface and having a second spatial array of optical inputs and a third spatial array of optical outputs;
- and
- an array of waveguide arms, each waveguide arm connecting one optical output of the first spatial array to a corresponding optical input of the second spatial array;
- and
- (b) applying (i) an optical input signal to a first optical input waveguide and (ii) a local-oscillator signal to a second optical input waveguide of the AWG to produce four different phase combinations of the optical input signal and the local-oscillator signal at a set of four optical outputs of the third spatial array.
5 more elements
An apparatus, comprising an arrayed waveguide grating (AWG) that comprises:
- a substrate having a planar surface;
- a first optical star coupler being along said surface and having first and second optical inputs and a first spatial array of optical outputs;
- a second optical star coupler being along said surface and having a second spatial array of optical inputs and a third spatial array of optical outputs;
- and
- an array of waveguide arms, each waveguide arm connecting one optical output of the first spatial array to a corresponding optical input of the second spatial array, wherein the array of waveguide arms is configured to cause a first set of four optical outputs of the third spatial array to receive four different phase combinations of light received at the first and second optical inputs in response to the light received at the first and second optical inputs being of about the same wavelength, wherein:
- the AWG is adapted to function as an n-channel wavelength demultiplexer, where n is a positive integer greater than one;
- and
- the third spatial array of optical outputs comprises 4n optical outputs, each for receiving a corresponding mixed signal that differs from each of the remaining (4n−1) mixed signals in at least one of (i) a carrier wavelength and (ii) a value of relative phase shift between the light applied to the first and second optical inputs.
5 more elements
An apparatus, comprising an arrayed waveguide grating (AWG) that comprises:
- a substrate having a planar surface;
- a first optical star coupler being along said surface and having first and second optical inputs and a first spatial array of optical outputs;
- a second optical star coupler being along said surface and having a second spatial array of optical inputs and a third spatial array of optical outputs;
- and
- an array of waveguide arms, each waveguide arm connecting one optical output of the first spatial array to a corresponding optical input of the second spatial array, wherein the array of waveguide arms is configured to cause a first set of four optical outputs of the third spatial array to receive four different phase combinations of light received at the first and second optical inputs in response to the light received at the first and second optical inputs being of about the same wavelength, wherein the array of waveguide arms has a periodic chirp pattern with a period of four waveguide arms, wherein the chirp pattern consists of:
- (i) two zeros,
- -
- λ
- c
- 8
- ,
- and
-
-
- 3
-
- λ
- c
- 8
- ;
- or
- (ii) two zeros,
- -
- 3
-
- λ
- c
- 8
- ,
- and
-
-
- λ
- c
- 8
- ,
- arranged in a selected order, where λc is a wavelength corresponding to one or more wavelength channels of the AWG.
34 more elements
Dependencies are inferred from the claim text.