In the fabrication of a polymeric arrayed waveguide grating (AWG) device, the cores of the channels and the arrayed waveguides exhibit smooth trapezoid cross-sections instead of originally designed rectangular ones after reactive ion etching and steam-redissolution. By employing the Marcatili theory, a method called “equivalent energy flow method” is proposed for analyzing the transmission characteristics of the polymeric AWG with trapezoid core cross-sections. The AWG parameters have been fixed, and a 17×17 polymeric AWG multiplexer has been designed and fabricated. Experimental results show that the central wavelength is 1550.83 nm, and the bandwidth at half maximum is about 0.478 nm; insertion loss is 10 to 13 dB, and crosstalk is about −21 dB .
A novel kind of wavelength-insensitive wide-spectrum polymer electro-optic (EO) switch is proposed by employing two symmetric active Mach-Zehnder interferometers (MZIs), a passive middle directional coupler and a pair of passive phase-generating couplers. Extinction ratio compensation condition under off-state and insertion loss compensation condition under on-state are derived to expand wavelength spectrum. With sufficient consideration of the wavelength dispersion of material and waveguide, optimization, and simulation were performed. The switch exhibits a switching voltage of 4.96 V with each MZI EO region length of 5000 μm. An S-C-L band (1460 to 1625 nm) covering a wide-spectrum more than 165 nm was obtained, and within this range, an extremely high extinction ratio more than 40 dB and an insertion loss within 1.8 to 11.9 dB were reached. This spectrum was more than 8 times of that of the traditional MZI EO switch (only 20 nm).The proposed device can function normally at any wavelength, and is an ideal candidate for a broadband photonic switching element in next-generation nonwavelength selective optical networks-on-chip.
A 33×33 thermo-optic tunable arrayed waveguide grating (AWG) is fabricated using the poly (2,3,4,5,6-pentafluorostyrene-co-glycidylmethacrylate) (PFS-co-GMA). The fabrication process of the device is depicted, and the measured results are presented. The measured insertion loss is between 8.5 dB for the central channel and 10 dB for the edge channels, the crosstalk is below −20 dB, the wavelength channel spacing is 0.8 nm, and the 3-dB bandwidth is 0.35 nm. The measured wavelength/temperature shift rate is about −0.12 nm/K. The central wavelength is 1545.21 to 1551.81 nm in the temperature range from 10 to 65°C. The tuning range is −6.6 nm.
In terms of the coupled mode theory, novel formulas of the transfer functions are presented for a microring resonator array, which consists of multiple series-cascaded filter elements, and each of them contains double parallel-cascaded identical microrings. By using these formulas, we can analyze transmission characteristics for such a polymer device. Simulated results show that when some parameters are selected properly, the box-like spectral response can be formed, which is flat and steep, and the sidelobes and the cross talk can be dropped efficiently. The effects of manufacturing tolerances on the transmittance are discussed, which result in the shift of the transmission spectrum of the device.
This paper proposes a design of polymer Triple Ring Resonators Filter (TRRF) based on silicon substrate. The device structure was demonstrated in order to get wide Free Spectral Ranger (FSR) of the device and a box-like filter response. The transmission equation of the amplitude of input and output lightwaves and coupling coefficients were analyzed by coupling mode theory also.
Based on formulas presented for the amplitude coupling ratio and the transfer function, transmission characteristics are analyzed and parameters are optimized for a polymer cross-grid array of microring resonant wavelength multiplexers around the central wavelength of 1.550918 µm with wavelength spacing 1.6 nm. In the design of the device, by means of selecting a resonant order m=95 and introducing a resonant order increment of adjacent filter elements m=2, we increase the ring radius difference of adjacent filter elements R from 17 nm (for the case of m=0) to 337 nm. Calculated results show that the 3-dB bandwidth is about 0.2 nm, the ratio between the –1- and –10-dB bandwidths is about 0.22, the insertion loss is less than 0.5 dB, and crosstalk is below –39 dB for each of the eight horizontal output channels.
Based on formulas presented, optimization design is performed and the effects of manufacturing tolerances on transmission characteristics are analyzed for a polymer microring resonant wavelength multiplexer around the central wavelength of 1.550918 µm with wavelength spacing 1.6 nm. Modeling results show that the insertion loss is less than 0.55 dB and crosstalk is less than –21 dB for each of eight vertical output channels of the designed device without tolerances. Some manufacturing tolerances result in a shift of the transmission spectrum and lead to increases of the inserted loss and crosstalk over the design case without tolerances
The diffraction characteristics are analyzed for a polymer arrayed-waveguide grating (AWG) multiplexer around the central wavelength of 1.55 μm with the wavelength spacing of 1.6 nm. The diffraction loss and diffraction efficiency in the input and the output slab waveguide are investigated and discussed for different values of parameters, such as the core width, pitch of adjacent waveguides, the number of arrayed waveguides, taper end width of waveguides, and number of output wavelength. Finally, we give a set of parameters which have been optimized in this device.
Based on the arrayed waveguide grating (AWG) multiplexer theory, some important parameters are optimized for the structural design of a polymer AWG multiplexer around the central wavelength of 1.55μm with the wavelength spacing of 1.6 nm. These parameters include diffraction order, focal length of slab waveguides, number of arrayed waveguides are determined. Then, a schematic waveguide layout of this device is presented, which contains 9 input and 9 output channels. The transmission and loss characteristics are analyzed. The computed results show that when we select the core thickness as 4 micron, width as 6 micron, pitch of adjacent waveguides as 26 micron, diffraction order number as 78, distance between the focal point and the origin as 8340 micron, the total loss of the device can be dropped to about 5.7dB, and the crosstalk among output channels can be dropped below -50dB.
In this paper, the basic principle, details of fabricating process and measuring results were described for a polymer/Si arrayed waveguide grating (AWG) multiplexer around the central wavelength of 1.550 micron with the wavelength spacing of 1.6nm. The fluorinated polymer was used to fabricate AWG to reduce the optical loss, but the fluorinated material was expensive, so we initially adopted the polymer of polymethylmethacrylate(PMMA) type to go on technologic research. The regulated curve of refractive index was given for the core polymer. In order to obtain better shape of the waveguide after the reactive ion etching (RIE) using oxygen, an aluminum film as mask was used on polymer instead of conventional photoresist as mask. In order to reduce radiation loss of underciadding layer to Si
substrate, the underciadding layer thickness was increased to 11 micron through two times of spin-coating, thus the radiation loss was reduced to the order of 0.001dB. The measuring results indicates fabricated optical waveguide achieved single-mode transmission.
An arrayed-waveguide grating multiplexer is demonstrated, which is successfully designed and fabricated . A wavelength channel spacing was 1 .6nm, a crosstalk of less than —20dB and the insertion loss was 7-12dB around 1.55?m. The polarization-dependent wavelength shift was very small without special compensation methods.
Under the condition of zero net strain, the effect of high temperature on the optical gain and threshold characteristics and the dependence of the characteristic temperature on the cavity length are analyzed theoretically for InGaAs/InGaAsP strain-compensated multiple quantum well (SCMQW) lasers lattice-matched to InP around 1.55 micrometers wavelength emission. The computed results show that as the temperature increases, both the threshold carrier density and the threshold current density increase. As the cavity length increases, the characteristic temperature increases and the temperature dependence becomes better. The characteristic temperature of a SCMQW laser is higher than that of a strain-compensated single quantum well (SCSQW) laser. Therefore, the temperature dependence of the SCMQW laser is better than that of the SCSQW laser. In addition, we find that in order to always keep 1.55 micrometers wavelength emission, certain relations exist among the well width, cavity length and temperature.
On the basis of the arrayed waveguide grating (AWG) multiplexer theory, some important parameters are optimized for the structural design of a polymer AWG multiplexer around the central wavelength of 1.55micrometers with the wavelength spacing of 1.6nm. These parameters include the thickness and width of the guide core, mode effective refraction indicees and group refractive index. Pitch of adjacent waveguides, diffraction order, path length difference of adjacent arrayed waveguides, focal length of slab waveguides, free spectral range, number of input/output waveguides, and that of arrayed waveguides.
We designed some important parameters and analyzed loss characteristics of a 8X8 polymer arrayed waveguide granting multuplexer that operates around the wavelength of 1.55 micrometers and the wavelength spacing was 16nm. The total loss of the device includes the diffraction loss in the input and output (I/O) slab waveguides, bent loss caused by the AWG and 1/O channels, and leakage loss resulted from the high refractive index substrate. The effects of some structural parameters on the loss characteristics are investigated and discussed. The computed results show that when we select the core thickness as 4 micrometers , core width as 6 micrometers , pitch of adjacent waveguides as 15.5 micrometers , diffraction order number as 50, the number of the arrayed waveguides as 91, that the I/O channels as 8,confined layer thickness between the core and the substrate as 6 micrometers , distance between the focal point and the origin as 5500 micrometers , and central angle between the central waveguide and the vertical of the symmetrical line of the device as 60 deg, then the total loss of the device can be dropped to about 3.73 dB.
KEYWORDS: Laser stabilization, Information operations, Optoelectronics, Transmission electron microscopy, Process modeling, Differential equations, Cladding
In this paper, the stability of strained MQWs in laser structure is discussed. The excess stress is the driving force of misfit dislocation multiplication and is a very important factor of strained MQWs stability. So we calculate the excess stress using the single-kink model. Our results show that the maximum position of excess stress is related to the barrier and well thicknesses and mismatches in the well(s). The lattice-matched barriers can dilute the excess stress. The capping layer can also dilute the excess stress in a certain degree. We then calculate the strain relaxation using the dynamic model of dislocations. In this model, the strain relaxation is driven by the excess strains. In this paper, the criteria of the stability of MQWs in laser structure is that the density of dislocations (or the strain relaxation) is less than a certain value. In this way, the barriers and capping layer are both important factors of MQWs stability. The method can be used to better the MQWs in laser structure.
In terms of the parameter interpolation principle, calculations are performed for bandgaps and band offsets in strain-compensated InzGa1-zAs/InxGa1-xAsyP1-y multiple quantum well structures on InP. Relations between strains and material compositions in InzGa1-zAs wells and InxGa1-xAsyP1-y barriers are analyzed, and relative ranges of strains are evaluated. Bandgaps of InzGa1-zAs wells and InxGa1-xAsyP1-y barriers for heavy- and light-holes are studied, and relative ranges of bandgaps are estimated. Dependence of band offsets of conduction band and valence band for heavy- and light-holes on strain compensation between InzGa1-zAs wells and InxGa1-xAsyP1-y barriers is investigated, and variation of band offsets versus strain compensation is discussed. The computed results show that strains, bandgaps and band offsets are functions of material compositions, strain compensation changes the band offsets, and hence modifies the band structures and improves the features of strain- compensated multiple quantum well optoelectronic devices.
In terms of the presented mode eigenvalue equation, the mode propagation and absorption loss are analyzed for Au/InGaAsP/nP, air/Au/InGaAsP/InP, and Au/SiO2/InGaAsP/InP single-mode metalclad multiple quantum-well optical waveguides. The effects of some guided structural parameters on the mode propagation and absorption loss are discussed, such as the periodic length, the ratio of the well thickness to the periodic length, the well number, and the thicknesses of the metal cladding and the dielectric buffer layer.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.