Abstract: Methods for modifying multi-mode optical fiber manufacturing processes are disclosed. In one embodiment, a method for modifying a process for manufacturing multi-mode optical fiber includes measuring at least one characteristic of a multi-mode optical fiber. The at least one characteristic is a modal bandwidth or a differential mode delay at one or more wavelengths. The method further includes determining a measured peak wavelength of the multi-mode optical fiber based on the measured characteristic, determining a difference between the target peak wavelength and the measured peak wavelength, and modifying the process for manufacturing multi-mode optical fiber based on the difference between the target peak wavelength and the measured peak wavelength.

Abstract: A differential mode delay (DMD) measurement system for an optical fiber is provided. The system includes an optical test fiber with a plurality of modes; a single mode light source that provides a continuous light wave signal to a modulator; and a pulse generator that provides an electrical pulse train signal to the modulator and a triggering signal to a receiver. The modulator is configured to generate a modulated optical test signal through the optical fiber based at least in part on the received light wave and pulse train signals, and the receiver is configured to receive the test signal transmitted through the fiber and evaluate the test signal based at least in part on the triggering signal. The system can be employed to create DMD waveform and centroid charts to obtain minEMBc bandwidth information for a fiber within a wavelength range.

Abstract: Methods for modifying multi-mode optical fiber manufacturing processes are disclosed. In one embodiment, a method for modifying a process for manufacturing multi-mode optical fiber includes measuring at least one characteristic of a multi-mode optical fiber. The at least one characteristic is a modal bandwidth or a differential mode delay at one or more wavelengths. The method further includes determining a measured peak wavelength of the multi-mode optical fiber based on the measured characteristic, determining a difference between the target peak wavelength and the measured peak wavelength, and modifying the process for manufacturing multi-mode optical fiber based on the difference between the target peak wavelength and the measured peak wavelength.

Abstract: Methods for modifying multi-mode optical fiber manufacturing processes are disclosed. In one embodiment, a method for modifying a process for manufacturing multi-mode optical fiber includes measuring at least one characteristic of a multi-mode optical fiber. The at least one characteristic is a modal bandwidth or a differential mode delay at one or more wavelengths. The method further includes determining a measured peak wavelength of the multi-mode optical fiber based on the measured characteristic, determining a difference between the target peak wavelength and the measured peak wavelength, and modifying the process for manufacturing multi-mode optical fiber based on the difference between the target peak wavelength and the measured peak wavelength.

Abstract: An optical fiber connection is provided that includes a first optical fiber defining a first exterior surface and a first effective area. The first fiber defines a first tapered region tapering from a first nominal fiber diameter to a first tapered diameter. A second optical fiber has a second exterior surface and a second effective area less than the first effective area. The second fiber defines a second tapered region tapering from a second nominal fiber diameter to a second tapered diameter and a fiber splice optically coupling the first tapered region of the first fiber to the second tapered region of the second fiber. The first and second tapered regions taper such that the first and second exterior surfaces have a variance from a Gaussian function of less than 25% of the Gaussian function at each point along the first and second exterior surfaces.

Abstract: Methods and apparatus for measuring the modal bandwidth of a multimode optical fiber as a function of wavelength are disclosed. The methods include emitting polarized light from a single-mode fiber, frequency-modulating the single-mode polarized light, and then conditioning the frequency-modulated polarized light to excite multiple modes of the multimode optical fiber. The multimode light transmitted by the multimode optical fiber is detected and analyzed by a network analyzer to determine a bandwidth for at least three different wavelengths. A controller performs a fit to the measured bandwidths using a fitting equation to determine the modal bandwidth as a function of wavelength.

Abstract: A method of measuring optical properties of a multi-mode optical fiber during processing of the fiber is described. The method includes: transmitting a light signal through one of the draw end of the multi-mode fiber and a test fiber section toward the other of the draw end and the test fiber section; and receiving a portion of the light signal at one of the draw end and the test fiber section. The method also includes obtaining optical data related to the received portion of the light signal; and analyzing the optical data to determine a property of the multi-mode fiber.

Abstract: A differential mode delay (DMD) measurement system for an optical fiber is provided. The system includes an optical test fiber with a plurality of modes; a single mode light source that provides a continuous light wave signal to a modulator; and a pulse generator that provides an electrical pulse train signal to the modulator and a triggering signal to a receiver. The modulator is configured to generate a modulated optical test signal through the optical fiber based at least in part on the received light wave and pulse train signals, and the receiver is configured to receive the test signal transmitted through the fiber and evaluate the test signal based at least in part on the triggering signal. The system can be employed to create DMD waveform and centroid charts to obtain minEMBc bandwidth information for a fiber within a wavelength range.

Abstract: Methods for modifying multi-mode optical fiber manufacturing processes are disclosed. In one embodiment, a method for modifying a process for manufacturing multi-mode optical fiber includes measuring at least one characteristic of a multi-mode optical fiber. The at least one characteristic is a modal bandwidth or a differential mode delay at one or more wavelengths. The method further includes determining a measured peak wavelength of the multi-mode optical fiber based on the measured characteristic, determining a difference between the target peak wavelength and the measured peak wavelength, and modifying the process for manufacturing multi-mode optical fiber based on the difference between the target peak wavelength and the measured peak wavelength.

Abstract: Methods and apparatus for measuring the modal bandwidth of a multimode optical fiber as a function of wavelength are disclosed. The methods include emitting polarized light from a single-mode fiber, frequency-modulating the single-mode polarized light, and then conditioning the frequency-modulated polarized light to excite multiple modes of the multimode optical fiber. The multimode light transmitted by the multimode optical fiber is detected and analyzed by a network analyzer to determine a bandwidth for at least three different wavelengths. A controller performs a fit to the measured bandwidths using a fitting equation to determine the modal bandwidth as a function of wavelength.

Abstract: A method of measuring optical properties of a multi-mode optical fiber during processing of the fiber is described. The method includes: transmitting a light signal through one of the draw end of the multi-mode fiber and a test fiber section toward the other of the draw end and the test fiber section; and receiving a portion of the light signal at one of the draw end and the test fiber section. The method also includes obtaining optical data related to the received portion of the light signal; and analyzing the optical data to determine a property of the multi-mode fiber.

Abstract: A method of measuring the bandwidth of a multi-mode optical fiber using single-ended, on-line and off-line approaches and test configurations. The method includes: transmitting a light signal through the first end of a multi-mode fiber toward the second end of the multi-mode fiber, so that a portion of the light signal is reflected by the second end toward the first end of the multi-mode fiber; and receiving the reflected portion of the light signal at the first end of the multi-mode fiber. The method also includes obtaining magnitude and frequency data related to the reflected portion of the light signal at the first end of the multi-mode fiber; and analyzing the magnitude and the frequency data to determine a bandwidth of the multi-mode optical fiber. The length of the multi-mode fiber may also increase over time during testing.

Abstract: A method of measuring the bandwidth of a multi-mode optical fiber using single-ended, on-line and off-line approaches and test configurations. The method includes: transmitting a light signal through the first end of a multi-mode fiber toward the second end of the multi-mode fiber, so that a portion of the light signal is reflected by the second end toward the first end of the multi-mode fiber; and receiving the reflected portion of the light signal at the first end of the multi-mode fiber. The method also includes obtaining magnitude and frequency data related to the reflected portion of the light signal at the first end of the multi-mode fiber; and analyzing the magnitude and the frequency data to determine a bandwidth of the multi-mode optical fiber. The length of the multi-mode fiber may also increase over time during testing.

Abstract: A long haul optical fiber transmission system includes a transmitter having a modulated bit rate of at least 40 Gb/s. A receiver is optically coupled to the transmitter with a composite optical fiber span. The optical fiber includes a first optical fiber coupled to the transmitter and a second optical fiber coupled to the first optical fiber. The first optical fiber has an effective area of at least 120 ?m2, an attenuation of less than 0.180 dB/km, and a length L1 from about 30 km to about 90 km. The second optical fiber has an effective area of less than 120 ?m2, an attenuation of less than 0.180 dB/km, and a length L2. The sum of L1 and L2 is at least 160 km. The composite optical fiber span does not include a repeater along the length of the span between the transmitter and the receiver or any rare earth dopants.

Abstract: A long haul optical fiber transmission system includes a transmitter having a modulated bit rate of at least 40 Gb/s. A receiver is optically coupled to the transmitter with a composite optical fiber span. The optical fiber includes a first optical fiber coupled to the transmitter and a second optical fiber coupled to the first optical fiber. The first optical fiber has an effective area of at least 120 ?m2, an attenuation of less than 0.180 dB/km, and a length L1 from about 30 km to about 90 km. The second optical fiber has an effective area of less than 120 ?m2, an attenuation of less than 0.180 dB/km, and a length L2. The sum of L1 and L2 is at least 160 km. The composite optical fiber span does not include a repeater along the length of the span between the transmitter and the receiver or any rare earth dopants.