Devices based on fibers engaged to substrates with grooves

An optical device, comprising:

• a first fiber having a first fiber coupling port which is formed by removing a portion of fiber cladding to form an optical surface within a reach of an evanescent field of a guided mode in said first fiber;
• a first substrate engaged to said first fiber and having a first substrate surface where said first fiber coupling port is located;
• a second fiber having a second fiber coupling port which is formed by removing a portion of fiber cladding to form an optical surface within a reach of an evanescent field of a guided mode in said second fiber;
• and
• a second substrate engaged to said second fiber and having a second substrate surface where said second fiber coupling port is located and which faces said first substrate surface of said first substrate, said second substrate positioned to align said first and said second fiber coupling ports to allow for evanescent coupling therebetween,
• wherein said first fiber coupling port is responsive to a control signal to change said evanescent coupling, and
• wherein said wherein at least one substrate has an elongated groove to which a fiber section is engaged and a respective fiber coupling port is formed, and wherein said substrate has a through hole penetrating through said substrate and one section of said fiber section passes through said through hole.

A device, comprising:

• first and second fiber modules respectively formed on first and second substrates and respectively having first and second optical fibers,
• wherein a respective substrate in each fiber module comprises (1) first and second opposing substrate surfaces, (2) a first elongated groove formed over said first substrate surface, (3) at least one opening located at one end of said first elongated groove and formed through said substrate to extend between said first and second substrate surfaces, (4) a second elongated groove formed over said first substrate surface, and (5) a second opening located at one end of said second elongated groove and formed through said substrate to extend between said first and second substrate surfaces,
• wherein a respective optical fiber in each fiber module is engaged to said respective substrate to pass through said first and said second openings to have a first fiber portion in said first elongated groove, a second fiber portion in said second elongated groove, and a third fiber portion between said first and said second fiber portions positioned over said second substrate surface, and wherein fiber claddings of said first and said second fiber portions are removed to form first and second fiber coupling ports for evanescent coupling into or out of said respective optical fiber,
• wherein said first and said second fiber modules are positioned to have said first substrate surfaces face each other where said first and said second optical coupling ports of said first optical fiber are respectively coupled to said first and said second optical coupling ports of said second optical fiber to form a Mach-Zehnder interferometer,
• wherein said third fiber portion in said first optical fiber includes an adjustable section that is configured to respond to a control signal to cause a change in an optical path length of said third fiber portion, and
• wherein at least said first optical coupling port of one of said first and said second fibers is responsive to a control signal to change evanescent coupling.

A device, comprising:

• first and second fiber modules respectively having first and second fibers engaged to first and second substrates, respectively, each fiber module having a substrate which includes (1) first and second opposing substrate surfaces, (2) at least four elongated grooves formed over said first substrate surface and at least one elongated groove formed over said second substrate surface, and (3) a plurality of openings located at ends of said elongated grooves and formed through said substrate to extend between said first and second substrate surfaces and to connect said elongated grooves, wherein each fiber passes through said openings to have fiber portions over both substrate surfaces and to form at least four fiber coupling ports in said elongated grooves on said first substrate and at least a single fiber coupling port on said second substrate surface that is located between first two adjacent fiber coupling ports and second two adjacent fiber coupling ports, wherein each fiber coupling port is formed by partially removing fiber cladding to form a coupling surface within a reach of an evanescent field of a guided mode in said fiber,
• wherein said first and said second fiber modules are engaged to face respective first substrate surfaces to each other to form a first Mach-Zehnder interferometer by aligning said first two adjacent fiber coupling ports of said first fiber module to said first two adjacent fiber coupling ports of said second fiber module to allow for evanescent coupling between said first and said second fibers, and a second Mach-Zehnder interferometer by aligning said second two adjacent fiber coupling ports of said first fiber module to said second two adjacent fiber coupling ports of said second fiber module to allow for evanescent coupling between said first and said second fibers;
• a third fiber module having (1) a third substrate with a substrate surface facing said second substrate surface of said first substrate and including an elongated groove, and (2) a third fiber engaged in said elongated groove to have a third coupling port which is formed by removing a portion of fiber cladding to form a surface within a reach of an evanescent field of a guided mode in said third fiber, wherein said third fiber module is positioned to align said third coupling port to said single coupling port on said second substrate surface of said first substrate to allow evanescent coupling between said first and said third fibers;
• and
• a fourth fiber module having (1) a fourth substrate with a substrate surface facing said second substrate surface of said second substrate and including an elongated groove, and (2) a fourth fiber engaged in said elongated groove to have a fourth coupling port which is formed by removing a portion of fiber cladding to form a surface within a reach of an evanescent field of a guided mode in said fourth fiber, wherein said fourth fiber module is positioned to align said fourth coupling port to said single coupling port on said second substrate surface of said second substrate to allow for evanescent coupling between said fourth and said second fibers.