Km Of Single-mode Fiber Research Articles

1 Gbit/s optical FSK heterodyne transmission experiment over 100 km of single-mode fibre

A 1 Gbit/s optical FSK modulation/heterodyne detection transmission experiment has been conducted at a wavelength of 1497 nm. The receiver sensitivity is ?37dBm and no degradation is observed after transmission through 100 km of single-mode fibre.

Chromatic dispersion measurements on long fibre lengths using LEDs

The chromatic dispersion of 50.7 km of single-mode fibre has been measured with a single edge-emitting LED using the phase-shift technique. For a 15 s measurement time the zero of chromatic dispersion is obtained with a standard deviation of 0.7 nm for a 50.7 km fibre length and 0.25 nm for a 38.0 km length.

Two-way transmission using electro-optical modulator

A new method of simultaneous two-way transmission over one fibre is described. Only one optical source is required when an electro-optical modulator is used. In addition, the experimental results of a version of this system operating over 12 km of single-mode fibre are presented.

4-Gb/s transmission experiment over 117 km of optical fiber using a Ti:LiNbO3external modulator

We report a single-channel optical fiber data link with the largest bit-rate <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</tex> repeater spacing product achieved to date- ∼ 0.5 Tb . km/s. The multi-gigabit per second system is the first to incorporate a Ti:LiNbO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> external modulator as the data encoder.

Loss-limited transmission at 140 Mbit/s over 30 km of single-mode fibre using a 1.3 μm LED

Using an edge-emitting LED source, 140 Mbit/s was transmitted over 30 km of single-mode fibre. No penalty in receiver sensitivity due to chromatic dispersion was observed. The product of data rate and distance, 4.2 Gbit/skm, is the highest reported for loss-limited transmission over single-mode fibre using an LED source.

180 Mbit/s, 35 km transmission over single-mode fibre using 1.3 μm edge-emitting LEDs

Narrow-stripe, V-groove edge-emitting 1.3 μm LEDs are reported that couple -15.2 dBm of peak power into a single-mode fibre. Transmission at 180 Mbit/s over 35 km of single-mode fibre is described; this result corresponds to the highest bit rate-distance product (6.3 Gbit km/s) reported to date for an LED source. Accelerated aging results are presented.

Bidirectional transmission over 11 km of single-mode optical fibre at 34 Mbit/s using 1.3 μm LEDs and directional couplers

Results of a laboratory trial are reported in which bidirectional transmission at 34 Mbit/s over 11 km of single-mode fibre was demonstrated using 1.3 μm ELEDs, single-mode fused biconical tapered couplers and GaInAs PINFET receivers.

Chirp-free transmission over 82.5 km of single mode fibers at 2 Gbit/s with injection locked DFB semiconductor lasers

The spectral and modulation characteristics of injection locked distributed feedback lasers operating at 1.5-μm wavelength have been investigated. The total elimination of excess chirp in directly modulated lasers by the injection locking technique has allowed us to perform transmission experiments over 82.5 km of single mode fibers at 2 Gbit/s without any measurable penalty related to dispersion. Device design parameters for efficient chirp suppression are also given.

1.55-μm InGaAsP ridge waveguide distributed feedback laser

Optical and modulation properties of ridge waveguide distributed feedback lasers grown by liquid phase epitaxy and operating in the spectral region of 1.51–1.58 μm have been investigated. These lasers were characterized by room temperature cw threshold currents as low as 40 mA, external quantum efficiency of up to 40%, and lowest order transverse mode operation up to 10 mW. Stable, single longitudinal mode operation under direct modulation of up to 4 GHz was obtained using second order gratings fabricated by electron beam writing as well as optical holography. The absence of partition mode events has allowed routine error free transmission over 60 km of single mode fiber at data rates of 2 Gb/s. The relationship between grating parameters and the Bragg length has been studied experimentally and compared with the theoretical results.

Transmission properties of lightguide fibres coated at a line speed of 10 m/s

We report the transmission characteristics of high-speed-coated lightguide fibres; the evaluation is based on a total length of 90 km of single-mode fibre. For this experiment the line speed was varied from 2 to 10 m/s, and each sample length obtained from a preform was ~ 10 km. We found that the average losses of the fibres coated at three different speeds (2, 5 and 10 m/s) are all ~ 0.4 dB/km at 1.32 ?m.

Transmission experiment at 3 Gbit/s with close-spaced wavelength-division-multiplexed single-frequency lasers at 1.5 μm

We report the first fibre-optic transmission experiment employing close-spaced wavelength division multiplexing and high-bit-rate modulation. Experimental results from transmission at 3 Gbit/s over 60 km of single-mode fibre using two wavelength-multiplexed single-frequency distri-buted-feedback lasers are described. The lasers, operating at 1.55 μm and with a wavelength separation of only 2.9 nm, are each modulated at 1.5 Gbit/s giving a total system capacity of 180 Gbitkm/s.

1 Gbit/s transmission experiment over 101 km of single-mode fibre using a 1.55 μm ridge guide C 3 laser

Using a cleaved-coupled-cavity (C3) ridge guide laser which oscillates in a single longitudinal mode at 1.55 μm wavelength, we report the first lightwave transmission experiment exploying single-frequency lasers at speeds above 500 Mbit/s. We have achieved digital transmission with a bit-error rate of 2 × 10−10 at 1.0 Gbit/s over 101 km of single-mode fibre. This represents a record for the length of unrepeatered optical transmission for bit rates greater than 500 Mbit/s. Evidence for an error-rate floor, presumably due to residual partition noise, is observed. No such floor was observed in an 84 km—1 Gbit/s experiment using the same C3 laser.

OTDR in single-mode fibre at 1.55 μm using a semiconductor laser and PINFET receiver

Optical time domain reflectometry (OTDR) at a wavelength of 1.55 μm using a semiconductor laser source is reported for the first time. The apparatus uses a PINFET optical receiver and can detect the Rayleigh scatter signal over 30 km of single-mode fibre installed in duct.

Transmission experiments through 101 km and 84 km of single-mode fibre at 274 Mbit/s and 420 Mbit/s

Four transmission experiments through low-loss single-mode optical fibre at 1.3 μm have been performed at 274 Mbit/s and 420 Mbit/s with different objectives. The first demonstrates transmission through 101 km of single-mode fibre at 274 Mbit/s with negligible dispersion penalty. The second experiment at 274 Mbit/s and 84 km uses only components suitable for use in an undersea cable system. Two additional experiments, both at 420 Mbit/s, accomplish a bitrate × distance product of 35 GHzkm with 84 km of fibre and show no dispersion penalty with 63 km and 2.4 ps/km nm dispersion.

Experiences with an optical long-haul 2.24 Gbit/s transmission system at a wavelength of 1.3 μm

The letter describes the problems which occurred in the course of the implementation of an experimental optical transmission system which operates at a bit rate of 2.24 Gbit/s over 21 km of single-mode fibre with commercially available optoelectronic components. The laser wavelength is 1.3 μm.

Single-mode optical fibre microbending loss in a loose tube coating

45 km of single-mode fibre of differing detailed design has been loose-tube packaged under identical conditions. The spectral loss between 1.1 and 1.75 μm was measured before and after packaging. The incremental loss thus deduced, and related to equivalent core size and Δn, provided information about fibre design for safe packaging.