MicronOptics (United States)

All-fibre distributed feedback (DFB) lasers providing continuous tuning over 27 nm are demonstrated for the first time. Extended wavelength coverage of the lasers is obtained using a simple bend-tuning technique which delivers undistorted outputs over the full tuning-range. We believe that the demonstrated devices are highly placed for application as tunable sources in future dynamic WDM optical communication networks that require all-optical wavelength tunability.

Single-frequency and single-polarization lasing can be generated in a compact self-injection locked fiber Fabry Perot laser with a short fiber Bragg grating feedback cavity without any discrete polarization control components. A 10 Gb/s NRZ transmission test demonstrates the laser's fiber communications.

Short-cavity erbium:ytterbium (Er/sup 3+/:Yb/sup 3+/) fiber Fabry- Perot lasers (FFPLs) are attractive as compact, stable and tunable single-frequency laser sources. However, the microcavity FFPLs output relatively small optical powers due to insufficient pump absorption of Er/sup 3+/:Yb/sup 3+/ fiber, longer cavity length (>1 mm) can enhance the output power, but it results in unstable multiwavelength lasing, and these FFPLs actually operate in two orthogonal polarizations. To overcome these difficulties, we recently proposed and demonstrated a single-frequency and single-polarization FFPL with self-injection locking. In this paper, we show the high performance of the 5mm long FFPL with self-injection locking for use in the 10Gb/s transmission system.

A 100-GHz soliton pulse train, with the potential of very low timing jitter, is generated using soliton compression of the beat signal between two optical carriers. The optical carriers are obtained by optically filtering out the third-order sidebands generated from a single DFB laser and a LiNbO/sub 3/ electro-optic phase modulator driven at 16.9 GHz. >

Erbium fiber lasers emitting in the 1.55um wavelength region have been under intensive research for applications in telecommunications, spectroscopy and sensors. To ensure single frequency operation, fiber lasers constructed with either Fabry-Perot cavities or ring cavities usually require wavelength filtering components such as external gratings [1], in-fiber gratings [2] and Fabry-Perot filters [3]. Wavelength tuning can subsequently be achieved by filter adjustments. Recently a microchip erbium:ytterbium (Er:Yb) phosphate-glass laser has achieved single-mode operation in a 200um Fabry-Perot cavity without additional filtering [4]. Here we report a compact tunable single-mode fiber laser using a novel combination of an Er:Yb phosphate-glass fiber (developed under contract to Amoco Technology Company) within a fiber Fabry-Perot (FFP) cavity [5]. Attractive features of Er: Yb phosphate glass include efficient pump absorption at 980nm by the Yb ions and a large stimulated-emission cross-section for the Er. FFP technology allows fabrication of very short cavities ( ~ 8um) and continuous wavelength tunability with low loss. Here we demonstrate the shortest Er: Yb phosphate-glass FFP laser ever reported, having a 100um cavity length and a continuous wavelength tuning range over 4.52nm, limited only by the sharp gain peak.

Generation of high-repetition-rate near-transform-limited soliton pulse trains using soliton compression of the beat signal between two CW lasers has shown promise as a source.[1-5] In previous work, two independent lasers were combined and compressed using custom decreasing- dispersion fiber or comb-like dispersion fiber. Since the repetition rate of the compressed pulse train equals the frequency separation between the two laser sources, a very high repetition rate can be achieved. However, the linewidth of the beat signal between the two laser sources leads to timing jitter. This timing jitter can represent a problem in that a high bandwidth phase lock loop is required to synchronize the source to an external pulse train or clock. The implementation of such a phase lock loop is further complicated by the large inherent delay in the fiber compressor (~ 10 - 100 μs). In this paper we demonstrate generation of near-transform-limited soliton pulse trains with the potential of very low timing jitter using a single laser source, a phase modulator, a fiber Fabry Perot filter, an erbium amplifier, and non-dispersion-tailored fiber that can be configured for high (123 GHz) and low (23 GHz) repetition rates. Also, demonstrated is accurate agreement of measured and simulated results and a 100 GHz to 10 GHz optical demultiplexing operation illustrating the timing stability of this new source.

Previous fiber Fabry-Perot scanning interferometers (FFPSI's) demonstrated bandwidth (BW) reaching 500 KHz.1 Since a FFPSI does not suffer diffraction losses or imperfect spatial mode matching, as do bulk Fabry-Perot scanning interferometers (FPSI's), very high resolution can be obtained with long cavity lengths.2 Here we describe achievement of a direct optical BW (resolution) of 4 KHz and report experimental observations and theoretical analysis of transmission fringe distortions due to the finite speed of light. For the first time, to our knowledge, we quantify the significant effects of scan time and cavity loss in long-cavity FFPSI's.