Douglas M. Baney

A simple intensity noise reduction technique for optical low-coherence reflectometry

It is shown that by attenuating the reference power in an optical low-coherence reflectometry (OLCR) measurement, the reflection sensitivity can be improved, even though, in many other types of optical measurements, sensitivity is improved as optical power is increased. The difference is due to the presence of inherent intensity noise associated with low-coherence sources, which can dominate over shot noise at optical powers that are as low as 1 mu W. A reflection sensitivity of -146 dB is demonstrated using this technique.<<ETX>>

Measurement of Rayleigh backscattering at 1.55 mu m with 32 mu m spatial resolution

Rayleigh backscattering at a wavelength of 1.55 mu m is measured in standard single-mode fiber with a spatial resolution of 32 mu m and a dynamic range of over 30 dB. A minimum reflection sensitivity of -148 dB is the best reported to date using optical low-coherence reflectometry.<<ETX>>

Extended-range optical low-coherence reflectometry using a recirculating delay technique

We propose a novel technique allowing for a substantial increase in the distance measurement range for optical low-coherence reflectometry. By introducing a recirculating delay into the interferometer reference path, we achieve a 100 times increase in range compared to previous optical low-coherence reflectometry techniques. At this extended range, a reflection sensitivity greater than -80 dB is demonstrated at a probe wavelength of 1.55 mu m.<<ETX>>

Simultaneous blue and green upconversion lasing in a laser‐diode‐pumped Pr3+/Yb3+ doped fluoride fiber laser

An upconversion laser operating simultaneously at visible wavelengths of 520 and 490 nm under infrared semiconductor pumping is demonstrated. The Pr3+/Yb3+doped ZBLAN fluorozirconate fiber laser yielded 1.4 mW total power at green and blue wavelengths with approximately 350 mW of incident pump light at a wavelength of 856 nm. Threshold launched powers of 55 and 85 mW were obtained for the wavelengths of 520 and 490 nm, respectively.

Multiplexed sensing using optical low-coherence reflectometry

A novel multiplexed optical sensor permitting absolute length measurement in remote reflective sensor arrays is proposed. Based on optical low-coherence reflectometry, this technique has been used to demonstrate length measurements to within 10 /spl mu/m for 6-m sensor cables situated 70 km from the receiver.<<ETX>>

WDM EDFA gain characterization with a reduced set of saturating channels

The advent of EDFA-based dense WDM places demanding optical source requirements for EDFA characterization. An iterative method is proposed here, based on a homogeneous amplifier model, to calculate the required signal conditions for WDM testing with a reduced set of saturating channels and a broad-band noise probe. EDFA gain measurements demonstrating this reduced-source technique agree to within 0.2 dB to those obtained with a four-channel WDM system operating near 1.55 /spl mu/m.

High-frequency photodiode characterization using a filtered intensity noise technique

Optical filtering of amplified spontaneous emission improves measurement dynamic range for frequency response measurements of optoelectronic receivers. For high bandwidth receivers, a novel periodically filtered intensity noise technique is proposed. Response measurements using these techniques on a 1 GHz and 30 GHz receiver are demonstrated.<<ETX>>

Gain and noise characterization of EDFAs for WDM applications

In summary, a number of methods have been developed, permitting accurate measurement of the gain and noise figure of WDM amplifiers. Gain and noise figure measurement methods for single-channel and WDM Er-doped fibre amplifiers have many similarities. The differences arise namely in the way the source spontaneous emission can be treated, the requirement of multiwavelength sources, and WDM specific gain measurement requirements.