Wavelength router

A wavelength router for receiving light having a first number, N, of spectral bands at an input port and directing subsets of the N spectral bands to respective ones of a second number, M, of output ports, the wavelength router comprising:

• a first optical element with positive optical power disposed to collimate light emanating from the input port;
• a transmissive dispersive element for dispersing the light in a first transverse dimension in a particular sense to spatially separate the spectral bands;
• a second optical element with positive optical power disposed to focus the light traveling from said dispersive element;
• and
• a plurality of retroreflectors in the focal plane of said second optical element, each retroreflector intercepting a respective spectral band and directing that spectral band back toward said second optical element with a transverse displacement in a second transverse dimension that is orthogonal to the first transverse dimension, said transverse displacement depending on a state of that retroreflector;
• wherein each spectral band is collimated by said second optical element, dispersed in the first transverse dimension by said dispersive element in a sense opposite the particular sense, and focused by said first optical element, whereupon each spectral band is brought to a focus at a respective position determined by the respective retroreflector.

A wavelength router for receiving light having a first number, N, of spectral bands at an input port and directing subsets of the N spectral bands to respective ones of a second number, M, of output ports, the wavelength router comprising:

• an optical element with positive optical power disposed to collimate light emanating from the input port;
• a reflective dispersive element for dispersing the light traveling from said optical element in a first transverse dimension in a particular sense to spatially separate the spectral bands, said dispersive element directing the spectral bands back to said optical element, which focuses the light traveling from said dispersive element;
• and
• a plurality of retroreflectors in the focal plane of said optical element, each retroreflector intercepting a respective spectral band and directing that spectral band back toward said optical element with a transverse displacement in a second transverse dimension that is orthogonal to the first transverse dimension, said transverse displacement depending on a state of that retroreflector;
• wherein each spectral band is collimated by said optical element, dispersed in the first transverse dimension by said dispersive element in a sense opposite the particular sense, and focused by said optical element, whereupon each spectral band is brought to a focus at a respective position determined by the respective retroreflector.

A wavelength router for receiving light having a first number, N, of spectral bands at an input port and directing subsets of the N spectral bands to respective ones of a second number, M, of output ports, the wavelength router comprising:

• a first cylindrical lens for collimating light emanating from the input port in a first transverse dimension;
• a second cylindrical lens for making the light traveling from said first cylindrical lens less divergent in a second transverse dimension that is orthogonal to the first transverse dimension;
• a reflective dispersive element for dispersing the light traveling from said second cylindrical lens, said light being dispersed in the first transverse dimension in a particular sense, said dispersive element directing the spectral bands at different angles back to said second cylindrical lens;
• the spectral bands traveling away from said dispersive element being collimated by said second cylindrical lens in the second transverse dimension and being focused by said first cylindrical lens in the first transverse dimension;
• and
• a plurality of N tiltable mirrors in the focal plane of said first cylindrical lens, each intercepting a respective spectral band and directing that spectral band back toward said first cylindrical lens;
• wherein each spectral band leaving its respective tiltable mirror is collimated in the first transverse dimension by said first cylindrical lens, partially focused by said second cylindrical lens in the second transverse dimension, dispersed in the first transverse dimension by said dispersive element in a sense opposite the particular sense, further focused in the second transverse dimension by said second cylindrical lens and focused in the first transverse dimension by said first cylindrical lens, whereupon each spectral band is brought to a focus in both the first and second transverse dimensions at an output port determined by the respective tiltable mirror.

A wavelength router for receiving light having a first number, N, of spectral bands at an input port and directing subsets of the N spectral bands to respective ones of a second number, M, of output ports, the wavelength router comprising:

• a first spherical lens having positive optical power;
• a transmissive dispersive element for dispersing light in a first transverse dimension;
• a second spherical lens having positive power;
• and
• a plurality of retroreflectors, each retroreflector intercepting a respective spectral band and directing that spectral band back toward said second spherical lens with a transverse displacement in a second transverse dimension that is orthogonal to the first transverse dimension, said transverse displacement depending on a state of that retroreflector;
• wherein:
• said first spherical lens, said dispersive element, said second spherical lens, and said plurality of N retroreflectors are disposed so that light emanating from the input port encounters, in order, said first spherical lens a first time, said dispersive element a first time, said second spherical lens a first time, said plurality of N retroreflectors, said second spherical lens a second time, said dispersive element a second time, and said first spherical lens a second time;
• said first spherical lens operates said first time to collimate the light, and said second time to focus the light on the output ports;
• said second spherical lens operates said first time to focus the light on said plurality of retroreflectors, and said second time to collimate the light;
• and
• said dispersive element operates said first time to impart an angular separation among the spectral bands in the first transverse dimension so that the spectral bands encounter their respective retroreflectors, and operates said second time to remove said angular separation among the spectral bands in the first transverse dimension;
• whereupon each spectral band is brought to a focus at an output port determined by the state of the respective retroreflector.

A wavelength router for receiving light having a first number, N, of spectral bands at an input port and directing subsets of said N spectral bands to respective ones of a second number, M, of output ports, the wavelength router comprising:

• a spherical lens having positive optical power;
• a reflective dispersive element for dispersing light in a first transverse dimension;
• and
• a plurality of retroreflectors, each retroreflector intercepting a respective spectral band and directing that spectral band back toward said spherical lens with a transverse displacement in a second transverse dimension that is orthogonal to the first transverse dimension, said transverse displacement depending on a state of that retroreflector;
• wherein:
• said spherical lens, said dispersive element, and said plurality of N retroreflectors are disposed so that light emanating from the input port encounters, in order, said spherical lens a first time, said dispersive element a first time, said spherical lens a second time, said plurality of N retroreflectors, said spherical lens a third time, said dispersive element a second time, and said spherical lens a fourth time;
• said spherical lens operates said first time to collimate the light, said second time to focus the light onto said plurality of N retroreflectors, said third time to collimate the light, and said fourth time to focus the light on the output ports;
• and
• said dispersive element operates said first time to impart an angular separation among the spectral bands in the first transverse dimension so that the spectral bands encounter their respective retroreflectors, and operates said second time to remove said angular separation among the spectral bands in the first transverse dimension;
• whereupon each spectral band is brought to a focus at an output port determined by the state of the respective retroreflector.

A wavelength router for receiving light having a first number, N, of spectral bands at an input port and directing subsets of the N spectral bands to respective ones of a second number, M, of output ports, the wavelength router comprising:

• a first cylindrical lens having positive optical power in a first transverse dimension;
• a second cylindrical lens having positive optical power in a second transverse dimension that is orthogonal to the first transverse dimension;
• a transmissive dispersive element for dispersing light in the first transverse dimension;
• a third cylindrical lens having positive optical power in the first transverse dimension;
• and
• a plurality of N tiltable mirrors, each tiltable mirror intercepting a respective spectral band and directing that spectral band back toward said second cylindrical lens with an angular displacement depending on a state of that tiltable mirror;
• wherein:
• said first cylindrical lens, said second cylindrical lens, said transmissive dispersive element, and said plurality of N tiltable mirrors are disposed so that light emanating from the input port encounters said first cylindrical lens a first time, said second cylindrical lens a first time, said dispersive element a first time, said third cylindrical lens a first time, said plurality of N tiltable mirrors, said third cylindrical lens a second time, said dispersive element a second time, said second cylindrical lens a second time, and said first cylindrical lens a second time;
• said first cylindrical lens operates said first time to collimate the light in the first transverse dimension, and said second time to focus the light in the first transverse dimension on the output ports;
• said second cylindrical lens operates said first time to collimate the light in the second transverse dimension, and said second time to focus the light in the second transverse dimension;
• and
• said third cylindrical lens operates said first time to focus the light in the first transverse dimension onto said plurality of N tiltable mirrors, and said second time to collimate the light in the first transverse dimension;
• said dispersive element operates said first time to impart an angular separation among the spectral bands in the first transverse dimension so that the spectral bands encounter their respective tiltable mirrors, and operates said second time to remove said angular separation among the spectral bands in the first transverse dimension;
• whereupon each spectral band is brought to a focus in both the first and second transverse dimensions at an output port determined by the state of the respective tiltable mirror.

A wavelength router for receiving light having a first number, N, of spectral bands at an input port and directing subsets of the N spectral bands to respective ones of a second number, M, of output ports, the wavelength router comprising:

• a first cylindrical lens having positive optical power in a first transverse dimension;
• a second cylindrical lens having positive optical power in a second transverse dimension that is orthogonal to the first transverse dimension;
• a reflective dispersive element for dispersing light in the first transverse dimension;
• and
• a plurality of N tiltable mirrors, each intercepting a respective spectral band and directing that spectral band back toward said first cylindrical lens with an angular displacement depending on a state of that tiltable mirror;
• wherein:
• said first cylindrical lens, said second cylindrical lens, said dispersive element, and said plurality of N tiltable mirrors are disposed so that light emanating from the input port encounters, in order, said first cylindrical lens a first time, said second cylindrical lens a first time, said dispersive element a first time, said second cylindrical lens a second time, said first cylindrical lens a second time, said plurality of N tiltable mirrors, said first cylindrical lens a third time, said second cylindrical lens a third time, said dispersive element a second time, said second cylindrical lens a fourth time, and said first cylindrical lens a fourth time;
• said first cylindrical lens operates said first time to collimate the light in the first transverse dimension, said second time to focus the light in the first transverse dimension onto said plurality of N tiltable mirrors, said third time to collimate the light in the first transverse dimension, and said fourth time to focus the light in the first transverse dimension on the output ports;
• said second cylindrical lens operates to collimate the light in the second transverse dimension upon passage of the light through said second cylindrical lens said first and second times, and to focus the light in the second transverse dimension upon passage of the light through said second cylindrical lens said third and fourth times;
• and
• said dispersive element operates said first time to impart an angular separation among the spectral bands in the first transverse dimension so that the spectral bands encounter their respective tiltable mirrors, and operates said second time to remove said angular separation among the spectral bands in the first transverse dimension;
• whereupon each spectral band is brought to a focus in both the first and second transverse dimensions at an output port determined by the state of the respective tiltable mirror.