A tunable interdigital electrode (TIE) DBR laser for single-currentcontinuous tuning

A tunable interdigital electrode distributed Bragg reflector (TIE-DBR) laser is proposed. The device provides single-current continuous-wavelength tuning without any external circuits, since the wavelength shift matching between the Bragg and the longitudinal cavity mode can be obtained in this structure. A continuous tuning in the 4.6-nm wavelength range with sufficient side-mode suppression is achieved with a 1.55-μm TIE DBR laser     

Continuously tunable photopumped 1.3-μm fiber Fabry-Perotsurface-emitting lasers

Continuously tunable, single-frequency, optically pumped semiconductor-fiber lasers are demonstrated that embody a half-cavity, vertical-cavity surface-emitting laser within a fiber Fabry-Perot cavity. Continuous wavelength tuning over 40 nm at 1300-nm wavelength region is obtained under continuous-wave operation     

Electrooptic tuning of a fiber ring semiconductor laser

This letter reports recent results obtained in the area of wavelength tuning of semiconductor lasers. The laser is constructed from an InGaAsP 1300-nm semiconductor optical travelling-wave amplifier. The cavity consists of a fiber ring resonator using a low fiber coupler as the output mirror. The intra-cavity electrooptic tuner works as a one-stage Lyot filter and allows wavelength tuning over a spectral range of 20 nm with a tuning rate of 0.05 nm V^-1. This is one of the best results reported using electrooptic birefringent tuning systems     

Diode-pumped and packaged acoustooptically tunableTi:Er:LiNbO3 waveguide laser of wide tuning range

Design, fabrication, and properties of an acoustooptically tunable Ti:Er:LiNbO₃ waveguide laser of up to 31-nm tuning range in the wavelength band 1530 nm<λ<1575 nm are discussed. The laser cavity is formed by an Au mirror and a dielectric mirror as output coupler, both vacuum-deposited on the polished waveguide endfaces. As tunable intracavity wavelength filter with zero frequency shift, two monolithically integrated single-stage acoustooptical TE-TM-mode converters are used together with two polarization splitters operated as TE- and TM-pass polarizers, respectively. The minimum threshold of about 54 mW (coupled) pump power is obtained at λ≈1561-nm emission wavelength for diode laser pumping at λ_p≈1480 nm. With about 110-mW coupled pump power, up to 320-μW output power is achieved; the emission linewidth is 0.3 nm     

Tunable wavelength conversion in a semiconductor-fiber ring laser

A tunable wavelength converter is demonstrated using highly nondegenerate four-wave mixing in a semiconductor-fiber ring cavity with no external pump light and low input signal power requirements. This device allows continuous tuning of both pump and converted wavelengths over the semiconductor optical amplifier gain bandwidth. Results for 11.8-nm down- and 6.9-nm up-wavelength conversion with input signal power as low as -10 dBm have been obtained at 1 Gb/s with less than 1.6-dB power penalty     

Tunable Optical Add&#8211;Drop Multiplexer Based on Silicon Photonic Wire Waveguides

A wavelength tunable optical add–drop multiplexer based on silicon photonic wire waveguides with Bragg-grating-reflectors was demonstrated by tuning the dropping wavelength through thermooptic effect. A 6.6-nm dropping wavelength shift was obtained at a 0.82-W heating power. For the device that is presently polarization-dependent, the 3-dB channel-dropping bandwidth was 0.4 nm and the extinction ratio at the dropping wavelength for port THROUGH was better than 17 dB for assuming 1.6-nm wavelength spacing dense wavelength-division multiplexing. The average tuning speed was about 200$muhboxs$.     

40-nm-wide tunable fiber ring laser with single-mode operationusing a highly stretchable FBG

We demonstrate a 750-Hz linewidth single-mode erbium-doped fiber (EDF) ring laser with wide tunability using a widely tunable fiber Bragg grating (FBG). The stable single-mode operation is realized by using the FBG as a narrow wavelength-selective element and 4 m of unpumped EDF as a saturable absorber in the cavity. The 40-nm continuous tuning range of 1522-1562 nm is achieved using a highly stretchable FBG that exhibits a filter tuning range of over 52 nm. The grating is prepared with chemically stripped deuterium-loaded fiber to eliminate degrading factors for the grating strength, thereby achieving the wide tunability. The tuning range represents a 3.5-fold increase in wavelength tuning over previous use of FBGs     

150-nm tuning range in a grating-coupled external cavityquantum-dot laser

An antireflection (AR) coated single-stack quantum-dot (QD) laser in a grating-coupled external cavity is shown to operate across a tuning range from 1.095 μm to 1.245 μm. This 150-nm range extends from the energy levels of the ground state to excited states. At any wavelength, the threshold current density is no greater than 1.1 kA/cm ². This large tunable range is the product of the rapid carrier filling of the higher energy states under a low pumping current and homogeneous broadening in the QD ensemble. The possibility of a larger tuning range is discussed with the further improvement of the AR-coating     

Compact Thermally Tunable Silicon Wavelength Switch: Modeling and Characterization

A wavelength-selective photonic switch is developed based on a Si microring resonator using thermooptic effect. The 10-mum-diameter microring resonator uses single-mode strip Si waveguides of dimension 0.25 mum times 0.45 mum operating at 1.5 mum. Full-width at half-maximum are in the range 0.1-0.2 nm. The ultrawide tunable range (>6.4 nm) and wide free spectral range (~18 nm) of the switch element enables wavelength reconflgurable multichannel matrix switch by wavelength multiplexing/demultiplexing. Average rise delay time of 14 mus with low switching power of 3.15 mW has been achieved with 0.2-nm wavelength tuning and 78 mus, 104 mW for 6.4-nm tuning. Fall delay times are usually less than 10 mus. Thermal simulations show 10%-20% agreement with the measurements up to 3.2-nm tuning. The compact size of the switch shows its potential as an active element in photonic integrated circuits.     

Experimental analysis of a broadly tunable InGaAsP laser with compositionally varied quantum wells

Custom-designed InGaAsP lasers have been fabricated, tested, and show a broad spectral output at a bias current of 240 mA. The Fabry-Perot ridge waveguide lasers were grown with one 80-/spl Aring/ and five 100-/spl Aring/ quantum wells in the active region. A different material composition was used for each well and this provided contributions to the gain profile over a broad wavelength range. A 1400-/spl mu/m cavity length laser was found to operate in the spectral region from 1475 to 1650 nm and single-mode operation on the individual Fabry-Perot modes of the uncoated laser was achieved over a 172-nm tuning range using a diffractive optical element short external cavity. The side-mode suppression ratio was measured to be above 30 dB at all wavelengths within the tuning range. Complete spectral coverage, in overlapping short segments, with the device is possible using temperature tuning.     

Liquid crystal mirror-based wavelength-tunable laser module with asynchronous mode cavity

We investigated experimentally the impact of the cavity spacing on the lasing mode stability of the external cavity wavelength-tunable laser (ECTL) with Fabry-Pe/spl acute/rot etalon and liquid-crystal-based wavelength-tunable mirror. In the asynchronous mode cavity ECTL, the etalon assists in the suppression of the cavity modes at the neighboring transmission peaks of the lasing wavelength due to the misalignment to the etalon's peak. Therefore, the ECTL with asynchronous mode cavity shows highly mode stable lasing operation. The fabricated ECTL module with optimized asynchronous mode cavity shows excellent lasing property of sidemode suppression ratio more than 59 dB and output power of over 14 dBm for a 45-nm tuning range.     

High-power high-Modulation-speed 1060-nm DBR lasers for Green-light emission

We report on the static and dynamic performance of high-power and high-modulation-speed 1060-nm distributed Bragg reflector (DBR) lasers for green-light emission by second-harmonic generation. Single-wavelength power of 387 mW at 1060-nm wavelength and green power as high as 99.5 mW were achieved. A thermally induced wavelength tuning of 2.4 nm and a carrier-induced wavelength tuning of -0.85 nm were obtained by injecting current into the DBR section. Measured rise-fall times of 0.2 ns for direct intensity modulation and 0.6 ns for wavelength modulation make the lasers suitable for >50-MHz green-light modulation applications.     

Wide-range tunability of GaInP-AlGaInP DFB lasers with superstructure gratings

Wide range wavelength tuning is demonstrated for short wavelength GaInP-AlGaInP distributed feedback lasers by controlling the injection currents in a two-section laser. Simple superstructure gratings were used to tune the emission wavelength over 4.9 nm in the 690-nm emission range. In a combination of current and temperature variation, the tuning range could be increased to more than 12 nm.     

A compact external cavity wavelength tunable laser without an intracavity etalon

We propose a novel external cavity wavelength tunable laser (ECTL) configuration without an etalon inside the cavity. ECTL consists only of a semiconductor optical amplifier with an integrated phase section, and a liquid crystal tunable mirror. We successfully demonstrated excellent performances of the ECTL with fiber coupled output power of more than 50 mW over a 40-nm tuning range, sidemode suppression ratio of better than 45 dB, relative intensity noise of better than -148 dB/Hz, and linewidth of narrower than 2.3 MHz.     

980-nm pump-band wavelengths for long-wavelength-band erbium-dopedfiber amplifiers

The impact of pump wavelength and input signal power on the output signal and backward spontaneous emission noise power of L-band erbium-doped fiber amplifiers is examined. It is shown experimentally that tuning the pump wavelength ±30-nm away from the 980-nm absorption peak provides 3-5-dB improvement in pump-to-signal conversion     

Tunable photonic crystal coupled-cavity laser

We report the development of a tunable photonic crystal coupled-cavity laser diode based on InP. The laser consists of two photonic crystal channel waveguides that are coupled through a photonic crystal mirror segment in /spl Gamma/-M direction. The cavity lengths define the respective mode spacings in the cavities. The tuning characteristics of the device are compared with results obtained from a transfer matrix model. Quasi-continuous tuning is achieved in a 29.6-nm window with 36 wavelength division multiplexing channels spaced 0.8 nm apart (ITU grid). The simplicity of fabrication and promising output characteristics should make this tunable laser design an interesting source for monolithic integration into highly integrated photonic circuits.     

Rapid continuous tuning of a single-polarization fiber ring laser

We have developed and studied what we believe is the first fiber laser operating in a single polarization at 1550 nm with PM fiber output and capable of wavelength tuning over a 20-nm bandwidth in less than 50 μs. The fast wavelength tuning speed in a fiber laser is achieved by incorporating an acousto-optic tunable filter into the laser. The same filter is used in an optoelectronic feedback loop to suppress the relaxation oscillations induced by wavelength transitions     

Subnanosecond tunable laser using a single electroabsorption tuning super structure grating

A new tunable laser structure using a single electroabsorption (EA) tuning super structure grating section for fast wavelength switching operation, has been realized. The tuning mechanism of this absorption change distributed Bragg reflector (DBR) laser is based on a localized absorption variation induced in a multielectrode EA-SSG section. These devices exhibit a 2.5-nm tuning range with three modes and a switching time, between two successive wavelength channels, shorter than 250 ps. The output power variation under tuning is lower than 1.2 dB.     

Wavelength Tuning of Vertical-Cavity Surface-Emitting Lasers by an Internal Device Heater

We have fabricated thermal-induced wavelength- tunable vertical-cavity surface-emitting lasers with a 780-nm emission wavelength that is tunable by using an internal device heater. A 5.36-nm tuning range was achieved by means of a 70-mA tuning current and a 3.5-mA driving current while maintaining continuous single-mode operation and the optical power variation is less than 2.5 dB in the tuning range. In addition, a multimode tuning range of 9.1 nm was achieved with a 90-mA tuning current and a 7-mA driving current.      

N-Type Doping to an Active-Short Cavity DBR Laser to Expand Its Continuous Tuning Range

We propose the use of a short-cavity distributed Bragg reflector (DBR) laser with a modified active DBR structure, which has an n-type-doped active single quantum well, and that achieves fast wavelength switching that is potentially applicable for optical packet switching networks. The laser exhibits 6.4-nm continuous tuning by moderating a steep gain change at a low DBR injection current. Furthermore, 32-nm continuous tuning has also been achieved for an integrated laser with an eight-channel array.