Showing papers in "IEEE Photonics Technology Letters in 1996"
TL;DR: In this paper, the difference in strain and temperature response of fiber Bragg gratings and a long period fiber grating was used to discriminate between strain induced and temperature induced wavelength shifts.
Abstract: We demonstrate a novel sensor which uses the difference in strain and temperature response of fiber Bragg gratings and a long period fiber grating to discriminate between strain and temperature induced wavelength shifts. Sensor interrogation is performed entirely on the fiber Bragg grating reflection signals. Strain and temperature were simultaneously measured to /spl plusmn/9 /spl mu/strain and /spl plusmn/1.5/spl deg/C over a wide range of conditions.
546 citations
TL;DR: In this article, the authors demonstrated simultaneous continuous wave multiwavelength operation of an erbium-doped fiber laser using two types of recently developed in-fiber grating comb filters.
Abstract: Simultaneous continuous wave multiwavelength operation of an erbium-doped fiber laser has been demonstrated using two types of recently developed in-fiber grating comb filters. The lasing wavelengths and linewidths were determined by the comb filter, which was inserted in a ring cavity with a single inhomogeneously broadened gain medium.
345 citations
TL;DR: It is numerically show that the synchronization of two chaotic semiconductor lasers is possible when a small amount of output intensity from one is injected into the other and a message can be encoded in the chaotic carrier and transmitted by an optical fiber and decoded by a receiver with a very good quality.
Abstract: We numerically show that the synchronization of two chaotic semiconductor lasers is possible when a small amount of output intensity from one Is injected into the other. We also show that a message can be encoded in the chaotic carrier, transmitted by an optical fiber and decoded by a receiver with a very good quality.
299 citations
TL;DR: In this paper, an erbium-doped fiber-ring laser with a low-loss cavity, controlled polarization evolution and liquid nitrogen cooling was used to achieve simultaneous lasing at up to 24 wavelengths.
Abstract: Simultaneous lasing at up to 24 wavelengths is demonstrated in an erbium-doped fiber-ring laser using a simple design. This result is achieved using a low-loss cavity, controlled polarization evolution and liquid nitrogen cooling to enhance spectral hole-burning, polarization hole-burning, and polarization selectivity. The design does not include any wavelength-selective components; instead, it utilizes wavelength selectivity provided by polarization evolution in the cavity. The amplitude variation between emission peaks is less than 3 dB over a 17-nm spectral range. A narrow linewidth of 0.15 nm, dense line spacing of 1.1 nm, and a good signal-to-noise ratio of more than 30 dB are achieved over most of the erbium bandwidth. The comb spectrum location and width are adjustable by changing and adjusting cavity components.
286 citations
TL;DR: In this article, a fiber Bragg transducer was used for the measurement of acceleration using interferometric wavelength-shift detection with a demodulated signal output range of 50g rms with a minimum detectable signal of /spl sim/1 mg/spl radic/Hz.
Abstract: We report a fiber Bragg grating transducer for the measurement of acceleration. Results obtained using interferometric wavelength-shift detection demonstrate a demodulated signal output range of 50-g rms with a minimum detectable signal of /spl sim/1 mg//spl radic/Hz.
237 citations
TL;DR: In this paper, the authors describe techniques for cascading the Brillouin/erbium fiber laser to generate optical combs, and experimentally demonstrate optical comb generation in the 1550-nm region.
Abstract: Brillouin/erbium fiber lasers, which have recently been demonstrated, operate with a combination of Brillouin gain and gain in erbium-doped fiber. In this letter, we describe techniques for cascading the Brillouin/erbium fiber laser to generate optical combs, and experimentally demonstrate optical comb generation. Internal and external cascading techniques are demonstrated. The line spacing in the combs is approximately 10 GHz, with operation in the 1550-nm region.
202 citations
TL;DR: In this paper, simultaneous laser operation of three single-frequency modes from an inhomogeneously broadened Er-doped twincore fiber loop laser is reported, achieving equal output power of 390 /spl mu/W, separation 0.5 nm, and linewidth <10 kHz.
Abstract: Simultaneous laser operation of three single-frequency modes from an inhomogeneously broadened Er-doped twincore fiber loop laser is reported. Equal output power of 390 /spl mu/W, separation 0.5 nm, and linewidth <10 kHz were measured for each mode in a travelling wave cavity comprising a single gain medium. In addition up to eight wavelength operation has been observed, demonstrating that twincore EDFA's can provide channel equalization in an eight-channel multiamplifier optical network.
183 citations
TL;DR: In this paper, a novel dispersion compensating fiber design consisting of two highly asymmetric concentric cores was proposed, which can have very large negative dispersion values with larger mode field diameter.
Abstract: We propose a novel dispersion compensating fiber design consisting of two highly asymmetric concentric cores. We show that the fundamental mode of the proposed fiber can have very large negative dispersion values [/spl sim/-5100 ps/(nm.km)] with larger mode field diameter (/spl sim/8-9 /spl mu/m) relative to the existing dispersion compensating fibers.
166 citations
TL;DR: In this article, the SOI rib waveguides fabricated by wet chemical etching have been shown to have field mismatch losses as low as 0.1 dB/cm at a wavelength of /spl lambda/=1.3 /spl mu/m.
Abstract: Waveguide losses as low as 0.1 dB/cm at a wavelength of /spl lambda/=1.3 /spl mu/m have been achieved in SOI rib waveguides fabricated by wet chemical etching. The single-mode waveguides have a large cross section yielding field mismatch losses to a standard single-mode fiber of only 0.17 dB/facet (both polarizations). Polarization independent fiber-chip-fiber insertion losses of 0.9 dB (best 0.5 dB) at a chip length of 60 mm have been measured.
157 citations
TL;DR: The perfectly matched layer (PML) boundary condition for the Helmoltz equation is developed and applied to the finite-difference beam propagation method in this paper, where its effectiveness is verified by way of examples.
Abstract: The perfectly matched layer (PML) boundary condition for the Helmoltz equation is developed and applied to the finite-difference beam propagation method. Its effectiveness is verified by way of examples.
141 citations
TL;DR: In this article, the authors suggest a new method for significantly enhancing the intrinsic bandwidth of a laser diode through the use of an injection locking technique, which shows that for moderate and high injection levels, the bandwidth can be increased to several times its free-running bandwidth.
Abstract: In this letter, we suggest a new method for significantly enhancing the intrinsic bandwidth of a laser diode through the use of an injection locking technique. Our analysis shows that for moderate and high-injection levels, the bandwidth of a laser diode can be increased to several times its free-running bandwidth.
TL;DR: In this article, a 40-Gb/s demultiplexer using an ultrafast nonlinear interferometer (UNI) was demonstrated, yielding incurred power penalties less than 3.3 dB for BER of 10/sup -9 dB.
Abstract: We demonstrate a 40-Gb/s demultiplexer using an ultrafast nonlinear interferometer (UNI). Bit-error-rate (BER) measurements are performed yielding incurred power penalties less than 3.3 dB for BER of 10/sup -9/.
TL;DR: In this paper, an exact analytical solution for the evolution of stimulated Raman crosstalk in a singlemode WDM fiber system is presented utilizing the triangular approximation to the Raman gain spectrum.
Abstract: An exact analytical solution for the evolution of stimulated Raman crosstalk in a singlemode WDM fiber system is presented utilizing the triangular approximation to the Raman gain spectrum. This approach provides a rigorous expression for crosstalk impairment. In the limit of small interchannel power exchange, our result reduces to Chraplyvy's previous estimate. Our formulation can be employed to predict the Raman penalty in future multiwavelength fiber communication systems.
TL;DR: In this article, a velocity-matched distributed photodetector (VMDP) was proposed for high-performance microwave fiber-optic links and high-power optical-microwave applications.
Abstract: A high-power, high-bandwidth photodetector is experimentally demonstrated using a novel velocity-matched distributed photodetector (VMDP). The distributed photodetector structure can achieve large absorption volume and high-saturation power while maintaining the high-speed performance of the fast photodiodes. The VMDP with 56 mA saturation photocurrent and an instrument-limited 3-dB bandwidth of 49 GHz is achieved. The results show that VMDP is ideal for high-performance microwave fiber-optic links and high-power optical-microwave applications.
TL;DR: In this article, a compact all-single-mode fiber add-drop multiplexer for dense wavelength-division-multiplexing systems is demonstrated, which consists of a polished fiber coupler with identical Bragg gratings within the interactive length.
Abstract: A novel compact all-single-mode fiber add-drop-multiplexer for dense wavelength-division-multiplexing systems is demonstrated. The device consists of a polished fiber coupler with identical Bragg gratings within the interactive length. The multiplexer operation has been theoretically analyzed and calculated transmission and reflection spectra are given. A fabricated prototype device shows good performance, but suffers from a high-insertion loss of 7 dB, which is due to the long but imperfect coupling region and can be drastically reduced in principle. A return loss >30 dB, coupling efficiency=99%, and bandwidth at FWHM /spl Delta//spl lambda/=1.2 mn was measured.
TL;DR: In this article, the authors reported the fabrication of a wavelength tunable optical filter using surface micromachining technology, which can be readily integrated with surface emitting lasers, modulators, and detectors.
Abstract: We report the fabrication of a wavelength tunable optical filter using surface micromachining technology. The center wavelength is 1.517 /spl mu/m and the transmission bandwidth is 5 nm. The device with a 50-/spl mu/m diameter aperture has an optical loss of about 5 dB. A continuous wavelength tuning of 60 nm has been demonstrated. This device may find applications in optical sensing and wavelength division multiplexing systems, and can be readily integrated with surface emitting lasers, modulators, and detectors.
TL;DR: In this paper, a 1 Tb/s aggregate capacity (50 channels each at 20 Gb/S) was transmitted through 55 km of nonzero-dispersion fiber, where 50 channels were generated by polarization multiplexing 25 wavelengths.
Abstract: A 1-Tb/s aggregate capacity (50 channels each at 20 Gb/s) was transmitted through 55 km of nonzero-dispersion fiber. Fifty channels were generated by polarization multiplexing 25 wavelengths.
TL;DR: In this paper, a novel add/drop filter for use in WDM optical fiber systems based on a Bragg grating assisted mismatched coupler is presented. But it is not interferometric, unlike all similar devices demonstrated so far, and therefore does not need fine tuning of the interferometers during fabrication and does not have to maintain the balance of the interferer during its lifetime.
Abstract: We have demonstrated a novel add/drop filter for use in wavelength-division-multiplexing (WDM) optical fiber systems based on a Bragg grating assisted mismatched coupler. The device is potentially easy to fabricate and stable, because it is not interferometric, unlike all similar devices demonstrated so far, and, therefore, does not need fine tuning of the interferometers during fabrication and does not have to maintain the balance of the interferometers during its lifetime.
TL;DR: In this article, an efficient, high-dynamic range microwave mixer implemented using an analog fiber-optic link with an overdriven optical modulator to produce the local oscillator requirement has been demonstrated and analyzed.
Abstract: An efficient, high-dynamic range microwave mixer implemented using an analog fiber-optic link with an overdriven optical modulator to produce the local oscillator requirement has been demonstrated and analyzed. This approach is compared with the heterodyned lasers approach to generating the local oscillator requirement and it is shown that increased conversion efficiency and more frequency and phase stable upconverted or downconverted signals are obtainable. Aside from RF link loss, which can be compensated with preamplification, a conversion loss below 5 dB has been demonstrated out to 10 GHz.
TL;DR: In this paper, the first observation of lasing from vertically self-organized multiple stacks of electronically uncoupled InAs three-dimensional island quantum boxes grown via molecular beam epitaxy on GaAs (001) substrates was reported.
Abstract: We report the first observation of lasing from vertically self-organized multiple stacks of electronically uncoupled InAs three-dimensional island quantum boxes grown via molecular beam epitaxy on GaAs (001) substrates. A low-threshold current density of 310 A/cm/sup 2/ at 79 K is found for a stack of five sets of islands corresponding to 2 ML InAs depositions separated by 36 monolayer GaAs spacers grown via migration enhanced epitaxy. The distribution of the island volumes (1.5/spl times/10/sup 5/ /spl Aring//sup 3/-4 /spl times/10/sup 5/ /spl Aring//sup 3/) gives, as expected, a multitude of laser lines between 980 mm and 996 nm.
TL;DR: In this paper, a sputter-deposited thin-film magnet was integrated onto a waveguide isolator fabricated in magnetic thin-filament garnets, achieving an isolation ratio of 29 dB with negligible excess loss.
Abstract: This letter describes the use of a compact sputter-deposited thin-film magnet that is directly integrated onto a waveguide isolator fabricated in magnetic thin-film garnets. Film magnets of different thicknesses are sputtered onto the waveguides, and isolation ratios of 29 dB are obtained with negligible excess loss. Stress-birefringent effects due to the ferromagnetic film overlayer are eliminated by the use of an aluminum compliant buffer.
TL;DR: In this paper, a multi-frequency laser (MFL) was demonstrated that runs simultaneously CW on 18 channels spaced by 103 GHz, with a stable and reproducible optical channel spacing owing to the reproducibility of the waveguide grating router.
Abstract: A multifrequency laser (MFL) is demonstrated that runs simultaneously CW on 18 channels spaced by 103 GHz. The laser emits -14.6-dBm power per wavelength channel into single-mode fiber. Each wavelength channel can be modulated at 1.24 Gb/s. The MFL exhibits a stable and reproducible optical channel spacing owing to the reproducibility of the waveguide grating router that serves as the intracavity filter element.
TL;DR: In this paper, a balanced photoreceiver was used to reject both laser intensity noise and noise added by an erbium-doped fiber amplifier, and the results of a 12-GHz downconverting optical link were presented that demonstrate shot-noise-limited performance at a maximum total photore receiver current of 72 mA.
Abstract: Experimental results of a 12-GHz downconverting optical link are presented that demonstrate shot-noise-limited performance at a maximum total photoreceiver current of 72 mA. A balanced photoreceiver is utilized to reject both laser intensity noise and noise added by an erbium-doped fiber amplifier. The receiver was constructed of four commercial 2-GHz photodetectors, each capable of detecting greater than 20 mA of average photocurrent with less than I-dB compression in received RF power.
TL;DR: In this paper, a single-port, reflective, waveguide modulator based on semiconductor laser amplifier technology was proposed, which achieved a reflection-mode chip gain of 17 dB at /spl lambda/=1.56 /spl mu/m.
Abstract: We describe a single-port, reflective, waveguide modulator based on semiconductor laser amplifier technology. The single-port geometry reduces the high packaging cost associated with two-port waveguide modulators, while the internal gain of the amplifier compensates for splitting and coupling losses. A modulator with a bulk active layer showed a reflection-mode chip gain of 17 dB at /spl lambda/=1.56 /spl mu/m. When driven with pseudorandom digital data at 100 Mb/s, extinction ratios of >12 dB were observed over the broad wavelength range (20 nm) needed for wavelength division multiplexed systems. Bit-error-rate tests confirmed that there was no distortion penalty, compared to a LiNbO/sub 3/ reference modulator.
TL;DR: In this article, a low-threshold lasing was achieved in oxidized vertical-cavity surface-emitting lasers incorporating upper dielectric distributed Bragg reflectors.
Abstract: Due to two improvements in cavity design, low-threshold lasing is achieved in oxidized vertical-cavity surface-emitting lasers incorporating upper dielectric distributed Bragg reflectors Intracavity absorption is reduced by removal of a heavily p-type contact layer and the use of a low-loss MgF-ZnSe upper mirror We report sub-100 /spl mu/A lasing for a 7-/spl mu/m diameter device, and sub-40 /spl mu/A lasing for a 3-/spl mu/m diameter device The low-loss cavity design also allows for highly multimode operation at a low-bias current of 600 /spl mu/A in a detuned cavity
TL;DR: In this article, the perfectly matched layer (PML) boundary condition is applied to modal analysis for optical waveguides and demonstrated that the PML is suitable and effective in computation of leaky modes.
Abstract: The perfectly matched layer (PML) boundary condition is applied to modal analysis for optical waveguides. It is demonstrated that the PML is suitable and effective in computation of leaky modes.
TL;DR: In this paper, an average signal gain of 26 dB was achieved for 8-channel WDM signals in the 1532-1560 nm wavelength region with a gain excursion of less than 1.5 dB at an input signal power of -20 dBm per channel.
Abstract: We successfully developed a fluoride-based Er/sup 3+/-doped fiber amplifier (F-EDFA). An average signal gain of 26 dB was achieved for 8 channel wavelength division multiplexed (WDM) signals in the 1532-1560 nm wavelength region with a gain excursion of less than 1.5 dB at an input signal power of -20 dBm per channel. Furthermore, we studied the amplification characteristics of the F-EDFA for WDM signals. The following experimental results were obtained. (1) For an 8-channel WDM signal in the 1532 to 1560 nm wavelength region, the gain excursion between channels can be suppressed to within 1.5 dB. However, the wavelength region allowing a gain excursion of 1.5 dB, is between 1536-1560 nm for the silica-based Er/sup 3+/-doped fiber amplifier. (2) F-EDFAs have a flat gain region between 1534-1542 nm. The gain excursion of this region is less than 0.2 dB for WDM signals.
TL;DR: In this paper, the authors describe how multimode interference couplers (MMI) may be used to broaden and flatten the passband of integrated wavelength-dispersive filters, and demonstrate their effectiveness with a passband-broadened InP arrayed waveguide filter operating at 1.5 /spl mu/m.
Abstract: We describe how multimode interference couplers (MMI) may be used to broaden and flatten the passband of integrated wavelength-dispersive filters. We discuss the approach and demonstrate its effectiveness with a passband-broadened InP arrayed waveguide filter operating at 1.5 /spl mu/m.
TL;DR: In this article, the authors report results of a system trial involving dispersion compensating chirped fiber gratings, demonstrating that transmission up to 537 km of standard telecommunications fiber is now feasible at 10 Gb/s, with a pair of 10-cm-long gratings cascaded together.
Abstract: We report on results of a system trial involving dispersion compensating chirped fiber gratings, demonstrating that transmission up to 537 km of standard telecommunications fiber is now feasible at 10 Gb/s, with a pair of 10-cm-long gratings cascaded together.
TL;DR: In this article, a novel integrated polarization converter based on ultra short bends is presented, which has a potential for low loss and small device size, and a conversion value of 85% was experimentally measured with excess loss of 2.7 dB and overall dimensions of 975/spl times/83 /spl mu/m.
Abstract: A novel integrated polarization converter based on ultra short bends is presented, which has a potential for low loss and small device size. A conversion value of 85% was experimentally measured with excess loss of 2.7 dB and overall dimensions of 975/spl times/83 /spl mu/m. Also 45% conversion was measured with extremely low excess loss of 0.4 dB for a device size of 760/spl times/86 /spl mu/m.