MEMS-tunable vertical-cavity SOAs

We present the signal gain, wavelength tuning characteristics, saturation properties, and noise figure (NF) of MEMS-based widely tunable vertical-cavity semiconductor optical amplifiers (VCSOAs) for various optical cavity designs, and we compare the theoretical results to data generated from a number of experimental devices. Using general Fabry-Pe/spl acute/rot relationships, it is possible to model both the wavelength tuning characteristics and the peak signal gain of tunable vertical-cavity amplifiers, while a rate-equation analysis is used to describe the saturation output power and NF as a function of the VCSOA resonant wavelength. Additionally, the basic design principles for an integrated electrostatic actuator are outlined. It is found that MEMS-tunable VCSOAs follow many of the same design trends as fixed-wavelength devices. However, with tunable devices, the effects of varying mirror reflectance and varying single-pass gain associated with the MEMS-based tuning mechanism lead to changing amplifier properties over the wavelength span of the device.     

底部出光纳米孔径面发射激光器的研究

在普通大功率垂直腔面发射激光器(VCSEL)基础上,制备出了底部出光纳米孔径VCSEL。利用聚焦离子束刻蚀技术完成纳米孔径的制作。当小孔直径为480nm×480nm时,测量得到器件的远场输出光功率为0.07mW。并分析了温度的变化对该器件远场输出光功率的影响。     

Development of bottom-emitting 1300-nm vertical-cavity surface-emitting lasers

We present experimental results on the development of bottom-emitting GaInNAs vertical-cavity surface-emitting lasers (VCSELs) operating at wavelengths near 1300 nm. This development effort is based on the modification of oxide-apertured top-emitting structures to allow emission through the GaAs substrate. Similar device performance was seen in both the top- and bottom-emitting structures. Single-mode output powers (adjusted for substrate absorption) of /spl sim/0.75 mW, with threshold currents of 1.3 mA, were achieved with /spl sim/3.5-/spl mu/m aperture diameters. Larger multimode devices exhibited a maximum adjusted output power of 2.2 mW. To the best of our knowledge, these are the first bottom-emitting flip-chip compatible 1300-nm VCSELs fabricated with GaInNAs-GaAs active regions.     

Widely tunable multichannel grating cavity laser

A widely tunable grating cavity laser based on the Rowland circle construction for a concave grating is proposed and demonstrated. The device is implemented by employing multichannel array structure in a Littman configuration and fabricated by integrating all elements in an InP substrate. Only one channel is turned on at a time, with coarse tuning realized by selecting the appropriate element in the channel array and fine tuning by controlling the beam deflection provided by dispersive element. An overall tuning range of 50 nm with a sidemode suppression ratio of more than 30 dB has been achieved for the six-channel device.     

Widely tunable single-frequency erbium-doped fiber lasers

In this letter, we report on experimental results on a 70-nm-wide quasi-continuously tunable single-frequency erbium-doped fiber (EDF) laser, in which the laser produced a single-longitudinal mode oscillation between 1510-1580 nm, an output power of 0.5 mW, and a tuning step of about 25 MHz. The cavity incorporates three tunable bandpass filters (TBFs): a bulk-grating-based TBF, a fiber-ring-cavity filter, and an autotracking saturable absorption-induced grating filter generated by an unpumped EDF. This laser had a frequency drift of 100 MHz and a signal-to-source spontaneous emission ratio higher than 60 dB.     

Widely tunable coupled-ring reflector laser diode

A coupled-ring reflector (CRR), which is composed of two coupled rings both of which are coupled with a straight waveguide, is applied to a widely tunable laser diode. When the radii of two rings are slightly different, the peak reflection wavelength of the CRR can be widely tuned over a few tens nanometers by a small amount of refractive index change. It is shown that a few tens nanometers of tuning with a sidemode suppression ratio exceeding 45 dB both for adjacent cavity mode and for adjacent ring mode is achievable in the widely tunable CRR laser diode.     

First demonstration of a MEMS tunable vertical-cavity SOA

We present the first microelectromechanical tunable vertical-cavity semiconductor optical amplifier. The device operates in the long wavelength range and exhibits a minimum of 10 dB of device gain through 11 nm of tuning.     

Widely tunable Y-coupled cavity integrated interferometric injection laser

A novel tunable single mode light source has been developed in the InGaAsP/InP material system. The Y-coupled cavity (YCC) type integrated interferometric injection (I/sup 3/) wavelength tunable laser operates in the 1300 nm wavelength region with a sidemode suppression of about 20 dB. By adjusting the currents through the four all active sections of this YCC-I/sup 3/-laser, a total tuning range of more than 14 nm and continuous tuning of 1.15 nm was obtained from non-optimised first devices.<>     

Widely tunable negative-chirp SG-DBR laser/EA-modulated transmitter

Ten Gb/s low power penalty (<0.5 dB) error-free transmission was achieved through 75 km using a high-performance sampled-grating (SG) distributed Bragg reflector (DBR) laser/EAM transmitter. Large signal chirp measurements show negative chirp operation across the entire tuning range of the devices. An integration-oriented quantum-well-intermixing (QWI) process was employed for the realization of these devices.     

Widely tunable chaotic fiber laser for WDM-PON detection

A widely tunable high precision chaotic fiber laser is proposed and experimentally demonstrated. A tunable fiber Bragg grating （TFBG） filter is used as a tuning element to determine the turning range from 1533 nm to 1558 nm with a linewidth of 0.5 nm at any wavelength. The wide tuning range is capable of supporting 32 wavelength-division mul- tiplexing （WDM） channels with 100 GHz channel spacing. All single wavelengths are found to be chaotic with 10 GHz bandwidth. The full width at half maximum （FWHM） of the chaotic correlation curve of the different wave- lengths is on a picosecond time scale, thereby offering millimeter spatial resolution in WDM detection.     

Flip-chip bonded 0.85-/spl mu/m bottom-emitting vertical-cavity laser array on an AlGaAs substrate

We report high-performance 0.85-/spl mu/m bottom-emitting vertical-cavity surface-emitting lasers (VCSELs) on an AlGaAs substrate with 2.1 mA threshold current density 4.2 mW maximum output power, 11.7% power conversion efficiency and a maximum operating temperature of 130/spl deg/C. We also demonstrate a flip-chip bonded 0.85-/spl mu/m bottom-emitting VCSEL array, and confirm all pixels across the 8/spl times/8 VCSEL array operate at a f/sub 3/ dB bandwidth of 2.6 GHz at only 4.2 mA.     

Widely tunable Mach-Zehnder interferometer laser with improved tuning efficiency

A successful realisation of widely tunable lasers based on a new design is presented. The lasers use a vertically integrated, electronically tunable Mach-Zehnder interferometer inside the resonator to select single Fabry-Perot resonances. With single-current tuning, a tuning range of 35 nm is experimentally demonstrated.     

Widely tunable sampled grating DBR laser with integratedelectroabsorption modulator

We report on the development of the first widely tunable semiconductor laser with an integrated electroabsorption modulator. The laser is a four-section buried-ridge sampled-grating distributed Bragg reflector design. It has a 41-nm continuous tuning range with a maximum tuning current of 23.5 mA for the hack mirror and 21 mA for the front mirror. The modulator is based on a 0.87-eV bandgap bulk waveguide structure. It is capable of producing more than 22 dB of optical extinction over the entire tuning range of the laser with a -4.0-V bias     

Widely tunable single-frequency Er-doped fiber laser with longlinear cavity

A widely tunable single-frequency Er-doped fiber laser is demonstrated in a 21-m-long linear cavity incorporating all-fiber acoustooptic frequency shifters and a saturable absorption grating. Stable single-frequency operation is achieved with a sidemode suppression ratio higher than 50 dB and a wavelength tuning range greater than 40 nm     

Widely tunable narrow linewidth erbium doped fibre ring laser

An erbium doped fibre ring laser enabling singlemode operation over a continuous wavelength tuning range of 44 nm (1528 nm-1572 nm) with laser linewidths of less than 10 kHz is reported.<>     

Widely tunable low-power high-linearity current-mode integrator built using DG-MOSFETs

A novel tunable current-mode integrator for low-voltage low-power applications is presented using mixed-mode TCAD simulations. The design is based on independently driven double-gate (IDDG) MOSFETs, a nano-scale four-terminal device, where one gate can be used to change the characteristics of the other. Using current-mirrors built with IDDG-MOSFETs, we show that the number of active devices in the tunable current-mode integrator, 16 in bulk CMOS design, may be halved, i.e. considerable savings in both total area and power dissipation. The integrator operates with single supply voltage of 1 V and a wide range of tunable bandwidth (~2 decades) and gain (~30 dB). This linear circuit has third-order harmonic distortion as low as ?70 dB in appropriate bias conditions, which can be set via the back-gates. The impact of tuning on the IDDG integrator and conventional design using symmetrically driven (SDDG) MOSFETs is comparatively studied. The proposed design is a good example for performance leverage through IDDG MOSFET architectures in analog circuits integral to future mixed-signal systems.     

Widely tunable mode-locked laser diodes using optical disk filter

We present a scheme for generating high-repetition-rate mode-locked optical pulses within a wide wavelength-tuning range. This scheme utilizes an external-cavity laser configuration with a disk-shaped bandpass filter (disk filter), which is set in the external cavity. The disk filter can tune its transmission wavelength by rotating parallel to the external mirror. This simple wavelength-tuning scheme allows a short external cavity, which is necessary for generating high-repetition-rate optical pulses. This paper describes a preliminary experimental demonstration exhibiting 100%-modulated mode-locked pulses at 8 GHz in the 1535-1587-nm range     

Widely tunable continuous-wave InGaAsP/InP sampled grating lasers

The 1.55 μm widely tunable sampled grating lasers described here show significant improvements over those previously reported. The authors have obtained, for the first time, continuous wave (CW) operation with 62 nm CW tuning range, 30-50 dB MSR, 10 mW output power, and monotonic tuning     

Widely tunable polarization-independent all-optical wavelengthconverter using a semiconductor optical amplifier

We report a polarization-independent widely tunable four-wave mixing wavelength converter using polarization diversity and broad-band orthogonal pumps in a single semiconductor optical amplifier. The conversion efficiency is nearly constant (less than 3-dB variation) over a 36-nm range with less than 0.34 dB polarization sensitivity. The power penalty at 10^-9 bit error rate for a 10-Gb/s signal is less than 0.9 dB     

Widely tunable polymer long-period waveguide grating with polarisation-insensitive resonance wavelength

A long-period waveguide grating in a polymer channel waveguide, which consisted of a benzocyclobutene core and an epoxy cladding, has been fabricated. By changing the stress in the waveguide through etching of the cladding width, a polarisation-insensitive resonance wavelength thermo-tunable from 1520 to 1610 nm with a temperature range of only 8/spl deg/C was achieved.