Patent ID: 9612155
Date: 2017-04-04
CPC Classifications: G01J,G02B,H04B

Claim:
1. A wavelength multiplexer/demultiplexer/spectrometer or compact curved grating spectrometer using discrete optical components or with integration possibility as a wavelength dispersion element in a photonic integrated circuit, enabling dispersiom of light spectra around a wavelength λ I1 , the wavelength multiplexer/demultiplexer/spectrometer comprising: at least one input slit; a plurality of output slits; and a curved grating, the curved grating configured for processing the spectra compositions of the optical beam including a plurality of grooves, the position of each groove being adjustable for controlling a performance of the wavelength multiplexer/demultiplexer/spectrometer, and the position of the input slit and each of the output slits being adjustable for controlling a performance of the wavelength multiplexer/demultiplexer/spectrometer, wherein the input slit allows an entry of the optical beam into the wavelength multiplexer/demultiplexer/spectrometer, a location of the input slit being adjustable, and further the location of the input slit X further wherein a first output slit for allowing the exiting of a first output optical beam having a first anchor output wavelength λ further wherein a medium in which the light propagates in having an effective refractive index of propagation “n wherein in the case of free space, n wherein in the case of a planar waveguide, n further wherein a position of the i wherein the given value of the input circle radius R where R is related to the input slit position by S where when given the first anchor output wavelength λ I1-O1A , the distance “d” is to be determined as follows: choosing a grating order and denoting the order by an integer “m”, and obtaining the grating parameter “d” from further wherein the locations of all other grooves are given by computing the coordinate of each groove with the i further wherein the locations of all other grooves are given by computing the coordinate of each groove with the i wherein D 1 (Θ I1 ,S I1 ,X i ) is the distance from X i to the first input slit location X I1 specified by θ I1 and S I1 , D 2 (Θ O1A ,S O1A ,X i ) is the distance from X i to the first anchor output slit location specified by θ O1A and S O1A , and the position of groove ja, X ja is typically already known, and a second condition such that a function f is equal to a numerical constant, functionally expressed as: where the above constant can be depending on other design parameters such as the input slit and output slit positions or the positions of the adjacent grooves (e.g. Θ I1 ,S I1 ,Θ O1 ,S O1 , λ I1-O1 , m, n gr , {X j }) that are already known and treated as part of the constant, wherein the positions {X j } represent the positions of some grating teeth that are already known, wherein the second constraint is further given by choosing the function f so that: wherein D 3 (θ O2A ,S O2A ,X i ) is the distance from the i-th groove located at X i to the second anchor output slit specified by a third angle θ O2A that is sustained between the line joining the second output slit to the grating center and a normal line of the grating center, and a second output distance S O2A from the grating center to the second output slit, wavelength λ I1-O2A is a second wavelength that is the wavelength for the second output slit given by: and by solving (2) and (4) for the x-coordinate x i and y-coordinate y i of the i th groove at X i =(x i , y i ), exact locations of other grooves X i 's are obtained, further wherein for more than one of the plurality of the output waveguides, the waveguide has a first tapering region forming the output mouth that tapered from the entrance mouth width to near or smaller than a waveguide width that supports only the fundamental mode, further wherein somewhere after the first tapering region is a first straight waveguide that can have zero length or a finite length, further wherein somewhere after the first straight waveguide is a section of first waveguide bending region, further wherein somewhere after the first waveguide bending region is a section of first waveguide fanning out region, further wherein somewhere after the first waveguide fanning out region is a second waveguide bending region to join the fanned out waveguide to a section of a first parallel propagating waveguide region, wherein at the first parallel propagating waveguide region, the adjacent waveguides are propagated almost parallel to each other, and the waveguide width is tapered out to larger than the fundamental mode width via a second tapering region, and close to the end of the first parallel propagating waveguide region, the waveguide is tapered back to near or smaller than the fundamental mode width via a third tapering region, further wherein after the third tapering region, is a section of a third waveguide bending region in which each waveguide undergoes a bending to connect to a second section of parallel propagating waveguide region, wherein at the second parallel propagating waveguide region, the adjacent waveguides are propagated almost parallel to each other, and the waveguide width is tapered out to larger than the fundamental mode width via a fourth tapering region, and close to the end of the second parallel propagating waveguide region, the waveguide is tapered back to near or smaller than the fundamental mode width via a fifth tapering region that can have a zero length or a finite length.