Optical fiber mode coupling device, having an optimized fiber interface and method of fabrication thereof

An optical fiber mode coupling device, having a first end supporting at least one desired fiber mode and a least one undesired fiber mode, and second end supporting at least one predetermined fiber mode, operable to maximize coupling between the at least one predetermined, fiber mode and the at least one desired mode, when positioned between a first optical fiber connected to the first end and a second optical fiber connected to the second end, further comprising:

• a first optical fiber mode coupling section comprising a first fiber core operable to support at least two spatial fiber modes, and having a third end, corresponding to the first end, configured for connection to the first fiber, and a fourth end having at least one supported mode, and being operable to achieve sufficiently strong coupling, between only at least one said desired mode and said at least one supported mode;
• a second optical fiber mode coupling section comprising a second fiber core operable to support at least one spatial fiber mode, and longitudinally and sequentially positioned after said first mode coupling section, having a fifth end corresponding to said fourth end, and an opposing sixth end, and being operable to substantially only allow said at least one supported mode to pass therethrough, while substantially removing all not supported fiber modes;
• and
• a third optical fiber mode coupling section comprising a third fiber core operable to support at least one spatial fiber mode, and longitudinally and sequentially positioned after said second mode coupling section, having a seventh end corresponding to said sixth end, and an opposing eighth end, corresponding to the second end, configured for connection with the second fiber of sufficiently high predetermined ruggedness, and being operable to achieve coupling, at said seventh end, between at least one supported fiber mode and the at least one predetermined mode.