Showing papers on "Insertion loss published in 1979"
TL;DR: In this article, a multireflection multi/demultiplexer using interference filters is proposed, where light waves of different wavelengths are combined or separated while they propagate between two filter arrays.
Abstract: A multireflection multi/demultiplexer using interference filters is proposed. Light waves of different wavelengths are combined or separated while they propagate between two filter arrays. The insertion loss of the 6-channel demultiplexer was around 1dB.
68 citations
PARC1
TL;DR: Biconically tapered fiber-optic star couplers with up to 100 fiber channels were reported in this paper. But the insertion losses were not as low as −0.56 dB and the normalised standard deviations of output poers as high as 4.4%.
Abstract: Biconically tapered fibre-optic star couplers with up to 100 fibre channels are reported which have excess insertion losses as low as −0.56 dB and normalised standard deviations of output poers as low as 4.4%
66 citations
TL;DR: The experimental results of a demultiplexer using a diffraction grating for a wavelength division multiplexing (WDM) system, which transmits signals with different wavelengths by means of a single optical fiber, are described.
Abstract: A wavelength division multiplexing (WDM) technique, which transmits signals with different wavelengths by means of a single optical fiber, can increase the capacity of optical fiber transmission systems. This paper describes the experimental results of a demultiplexer using a diffraction grating for a WDM system. The insertion loss of the demultiplexer could be decreased by using a large core output fiber, an Au-coated diffraction grating, and small aberration lenses. There were five channels in the 0.8-μm wavelength region. Wavelength spacing was 200 A. Insertion loss for each channel was about 2 dB, and cross talk was <−30 dB.
65 citations
TL;DR: In this article, a high-speed intensity modulator was fabricated taking advantage of the dependence of waveguide cutoff on its index of refraction, which consists essentially of a 2μm-wide 3.2mm-long Ti-diffused channel waveguide in y−cut LiNbO3.
Abstract: A high‐speed intensity modulator has been fabricated taking advantage of the dependence of waveguide cutoff on its index of refraction. The modulator consists essentially of a 2‐μm‐wide 3.2‐mm‐long Ti‐diffused channel waveguide in y‐cut LiNbO3. By controlling the propagation cutoff through the electro‐optic effect, an intensity modulation is obtained. The potential bandwidth, optical insertion loss, and specific energy at 0.63 μm are 5.3 GHz, 11 dB, and 230 μW/MHz, respectively. A brief analysis of modulator operation is given based on coupled‐mode theory.
53 citations
TL;DR: A low-loss small-sized demultiplexer using a diffraction grating in the Littrow mounting is realized for a wavelength division multiplexing (WDM) system for optical fiber systems.
Abstract: A low-loss small-sized demultiplexer using a diffraction grating in the Littrow mounting is realized for a wavelength division multiplexing (WDM) system for optical fiber systems. The system has five channels and a wavelength spacing of 200 A in the 0.8-μm region. Insertion loss was about 1.7 dB in each channel, and cross talk was <−30 dB. These characteristics make this demultiplexer the most suitable device available for optical fiber systems employing WDM configurations.
46 citations
TL;DR: A new crossing multimode channel waveguide electrooptical switch has a 21-dB ONstate/OFF-state difference at 10 V of applied voltage, 0.4-dB insertion loss, 2-pF capacitance, and a total length less than 1.5 mm.
Abstract: A new crossing multimode channel waveguide electrooptical switch is described here. It has a 21-dB on-state/off-state difference at 10 V of applied voltage, 0.4-dB insertion loss, 2.2-pF capacitance, and a total length less than 1.5 mm. It will be useful for providing a switching network for realizing an integrated optical computer communication data bus where electric signals from computers are converted into optical signals, switched by these switches, and then received and reconverted into electrical signals by a detector array.
46 citations
TL;DR: In this article, a simple modified balanced bridge modulator or switch is reported, consisting of only straight waveguides and an ion-etched slot used for a conventional phase shifter.
Abstract: A simple modified balanced bridge modulator or switch is reported. The modulator is comprised of only straight waveguides and an ion‐etched slot used for a conventional phase shifter. The slot excavated at the center of two coupled waveguides solves the coupling of them. 3‐dB coupler monitoring is performed here by a metal loading. The modulator is fabricated by diffusing Ti into z‐cut LiNbO3. Each patterned waveguide is fabricated by diffusing Ti into z‐cut LiNbO3. Each patterned waveguide is 7 μm wide and the spacing is 7 μm. The 3‐dB coupler is 2.9 mm long, and the excavated slot is 15 mm long, 4 μm wide, and 4.5 μm deep. The overall length is 20.8 mm. For the TM‐like fundamental mode, the half‐wave voltage was 2.8 V, the extinction ratio was −15 dB, and the optical insertion loss was as low as 2.6 dB at the 1.15‐μm wavelength.
43 citations
TL;DR: An adjustable access coupler for multimode fiber-optic networks has been constructed, based on the voltage-tunable total-internal-reflection effect in nematic liquid crystals, using a achromatic four-port switch.
Abstract: An adjustable access coupler for multimode fiber-optic networks has been constructed, based on the voltage-tunable total-internal-reflection effect in nematic liquid crystals. Fibers are coupled via graded-index rod lenses at normal incidence to flint-glass prisms in contact with a 6-μm liquid-crystal layer. The achromatic four-port switch has a 1.6-dB optical insertion loss, a tap ratio controllable from −4.6 to −48 dB, a directionality of 44 dB, and an operating voltage of 5 to 20 V rms.
42 citations
TL;DR: In this paper, the authors report on measurements of the near-field intensity distribution of single-mode T-diffused LiNbO 3 waveguides and on the alignment tolerances when coupled to a single mode fiber.
40 citations
Patent•
18 Dec 1979TL;DR: In this article, an integrated optical wavelength demultiplexer has been proposed for collimating light from an optical fiber and focussing light at an array of photodetectors formed under the waveguide layer.
Abstract: An integrated optical wavelength demultiplexer has deposited on a waveguide layer a pair of Luneburg lenses, the first for collimating light from an optical fiber, the second for focussing light at an array of photodetectors formed under the waveguide layer. Between the lenses is the dispersive element, a thin-film prism of a highly dispersive low-loss material such as arsenic trisulfide. A known integrated optical demultiplexer, which uses a chirped diffraction grating to spatially disperse (rather than angularly disperse) the optical wavelengths, would suffer a greater insertion loss particularly for wavelengths coupled out at a later point in the grating. Demultiplexing with a thin-film prism should also result in the capability to handle a larger number of channels, for a given channel isolation and substrate area.
38 citations
TL;DR: In this article, the beam transformation in a graded index rod (beam undulation and beam size change), in association with reflection or refraction at a grade index rod facet, is proposed to realize coupling/branching in fiber-optic communications.
Abstract: A novel approach, “micro-optics”, is proposed to realize coupling/branching in fiber-optic communications. The operation is based on the beam transformation in a graded index rod (beam undulation and beam size change), in association with reflection or refraction at a graded index rod facet. Small-size couplers/dividers have been devised by inserting a semitransparent mirror between the facets of two graded index rods with a length of a quarter of the undulation period. Their best features are small size, simple structure, low insertion loss, and wide application areas. An excess insertion loss as low as 0.5 dB has been realized in a 3-dB divider with SELFOC® rods. As further applications of them, wavelength division multiplexers/demultiplexers have been developed by replacing the semitransparent mirror with a dielectric interference filter. An insertion loss of as low as 1.2 dB and isolation of more than 20 dB for wavelength separation of 20 nm have been realized. Results are also shown on the o...
01 Jan 1979
TL;DR: In this paper, the authors present an introduction to Surface-Acoustic-Wave (SAW) devices, their operation, advantages, and applications, and the process of design and realization of high-performance SAW filters is examined from initial specifications to final device operation.
Abstract: An introduction to Surface-Acoustic-Wave (SAW) devices-their operation, advantages, and applications--is presented. The process of design and realization of high-performance SAW filters is examined from initial specifications to final device operation. Several techniques drawn from a variety of disciplines illustrate the implementation of finite impulse response SAW frequency functions. Material properties, transducer weighting, and computer-aided design are treated. An example of the design and testing of a 321-MHz 0.35-percent bandwidth, 65-dB sidelobe, 15-dB insertion loss filter is presented.
TL;DR: In this paper, a simple polarisation independent optical circulator was developed, consisting of a 45°Y3Fe5O12 rotator and a quartz rotator, and two polarising beam-splitting cubes.
Abstract: A simple polarisation-independent optical circulator has been developed. The circulator consists of a 45°Y3Fe5O12 rotator and a quartz rotator and two polarising beam-splitting cubes. Measured insertion loss was about 1.3 dB at 1.32 ?m wavelength. The circulator was connected to graded-index multimode fibres using rod lenses.
TL;DR: The optical losses due to butt-joining a single-mode optical fiber to a 32-microm wide Ti-diffused LiNbO(3) waveguide have been investigated and a numerical evaluation of the overlap integral of the fiber and waveguide mode profiles agrees with the measured loss.
Abstract: The optical losses due to butt-joining a single-mode optical fiber to a 32-μm wide Ti-diffused LiNbO3 waveguide have been investigated. Measurements of the total insertion loss as a function of waveguide length show that the waveguide attenuation is 1.25 dB/cm and that coupling losses as low as 0.5 dB can be achieved. The coupling loss has been calculated by a numerical evaluation of the overlap integral of the fiber and waveguide mode profiles, and the results agree with the measured loss.
01 Jan 1979
TL;DR: In this paper, a small sized Diplexer with high selectivity and low insertion loss for 800 MHz band land mobile communication systems has been developed using two port quarter wave coaxial dielectric resonators.
Abstract: Small sized Diplexer with high selectivity and low insertion loss for 800 MHz band land mobile communication systems has been developed using two port quarter wave coaxial dielectric resonators. A couple of resonators including inductive film electrode construct a compact resonance unit of the Diplexer and it is coupled by capacitive air gap spacings which operates as a part of J-inverter.
TL;DR: In this article, a low-loss and high-repeatability 4 × 4 optical matrix switch fabricated by using rhombic glass-block switch elements was described, and the maximum loss was 1.3 dB and the crosstalk was less than −55 dB, with a switching delay of less than 18 ms.
Abstract: A low-loss and high-repeatability 4 × 4 optical matrix switch fabricated by using rhombic glass-block switch elements is described. The maximum loss was 1.3 dB and the crosstalk was less than −55 dB, with a switching delay of less than 18 ms.
TL;DR: In this article, a balanced bridge-switch configuration with two 3dB couplers and an electro-optic phase shifter formed only by two parallel straight waveguides is presented.
Abstract: A new balanced‐bridge‐switch configuration is presented. This configuration has two 3‐dB couplers and an electro‐optic phase shifter formed only by two parallel straight waveguides. That is, these three regions were directly interconnected through no extra waveguides. The phase shifter was realized by unsynchronizing the phase of two adjacent waveguides by loading a high‐index film on one of them. The modified balanced‐bridge switch was fabricated in c‐plate LiNbO3 using Ti‐diffused waveguides and a Se‐S–based chalcogenide glass film. Waveguide dimensions were 8‐μm width, 5‐μm gap, and 16‐mm interaction length. Switch characteristics at 1.15‐ μm wavelength were 3.3 V half‐wave voltage, 8.7‐dB crosstalk, and 4.2‐dB insertion loss.
Patent•
08 Nov 1979TL;DR: In this paper, an optical switch for changing over the mode connecting two optical transmission lines comprising two optical fibers directly to each other and an optical communication device between the two transmission lines is described.
Abstract: Disclosed is an optical switch for changing over the mode connecting two optical transmission lines comprising two optical fibers directly to each other and the mode connecting an optical communication device between the two transmission lines. In this optical switch, in order to reduce the insertion loss, first, second, third and fourth optical fibers, each having an optical connector attached to one end, are attached to a substrate so that at least parts of the respective optical fibers are fixed to the substrate, and the ends of the first and second fibers are arranged on the substrate movably so that the end face of the first optical fiber confronts the end faces of the second and third optical fibers and the end face of the second optical fiber confronts the end faces of the first and fourth optical fibers.
TL;DR: In this article, the results of theoretical and experimental studies of microwave delay line filters based on magnetostatic wave propagation in epitaxial yttrium iron garnet (YIG) with multielement transducer pairs for wave launching and receiving are reported.
Abstract: This paper reports results of theoretical and experimental studies of microwave delay line filters based on magnetostatic wave (MSW) propagation in epitaxial yttrium iron garnet (YIG) with multielement transducer pairs for wave launching and receiving. Filter transmission and input impedance characteristics for both magnetostatic surface wave (MSSW) and magnetostatic forward volume wave (MSFVW) devices have been calculated and measured experimentally. A planar, multilayer metal‐dielectric‐YIG geometry, permitting consideration of decoupling due to spacing between the transducers and YIG surface, is used to model the transducer. A ’’low’’ loss microstrip transmission line model is used to derive an equivalent transducer circuit. For assumed noninteraction of transducer element currents, the Poynting vector is used to determine the radiation resistance and the radiation reactance is derived from the Hilbert transform of this resistance. Experimental swept frequency measurements of insertion loss and input i...
TL;DR: In this paper, a four-region model of a non-reciprocal dielectric-ferrite loaded stripline phase shifter employing the edge-guided dynamic mode is presented.
Abstract: Results of a theoretical study are presented for a four-region model of a nonreciprocal dielectric-ferrite loaded stripline phase shifter employing the edge-guided dynamic mode. The behavior of our model in terms of the differential phase shift, the insertion loss, and the effective bandwidth is explored as a function of the various parameters involved.
TL;DR: A new type of optical switch is constructed of graded-index rod lenses operated mechanically by small electromagnets and has many outstanding features, such as low insertion loss, low crosstalk, and small size.
Abstract: A new type of optical switch is constructed of graded-index rod lenses. It is operated mechanically by small electromagnets. This switch is compatible with practical multimode-fiber communication systems. It has many outstanding features, such as low insertion loss (1.3–1.4 dB), low crosstalk ( 2 × 106 times), and small size (40 × 50 × 25 mm3).
TL;DR: Strip waveguides having half-paraboloid shaped tapers that permit efficient fiber to waveguide coupling have been fabricated by Ag ion exchange in soda-lime glass with a reduction in the input coupling loss has been accomplished by tailoring the diffusion.
Abstract: Strip waveguides having half-paraboloid shaped tapers that permit efficient fiber to waveguide coupling have been fabricated by Ag ion exchange in soda-lime glass. A reduction in the input coupling loss has been accomplished by tailoring the diffusion to provide a gradual transition from a single-mode waveguide to a multimode waveguide having cross-sectional dimensions comparable to the core diameter of a single-mode fiber. Waveguides without tapers exhibit an attenuation of 1.0 dB/cm and an input coupling loss of 0.6 dB. The additional loss introduced by the tapered region is 0.5 dB. By way of contrast, an input coupling loss of 2.4 dB is obtained by coupling directly to a single-mode waveguide, indicating a net improvement of 1.3 dB for the tapered waveguides.
TL;DR: In this paper, a simple tuning network is presented for tuning of group type unidirectional transducers using a maximum of two elements and in special cases requires only a siigle external element.
Abstract: Abstroct-A simple tuning network is presented for tuning of group type unidirectional transducers. The method of tuning described uses a maximum of two elements and in special cases requires only a siigle external element. Experimental results for a filter having a 6.3dB insertion loss and a triple transit echo suppressed -44 dB using the described method verifies the analysis.
TL;DR: In this paper, a new approach to controlling millimeter wave propagation with light was demonstrated, where phase shifts as high as 300°/cm of 94 GHz millimeter waves were observed accompanied by less than 1 dB insertion loss.
Abstract: We have demonstrated a new approach to controlling millimeter wave propagation with light. Phase shifts as high as 300°/cm of 94‐GHz millimeter waves were observed accompanied by less than 1 dB insertion loss. A straightforward model was found to account in detail for the observed behavior.
Patent•
11 Jan 1979
TL;DR: In this article, the insertion loss measurement at microwave frequencies is achieved using an improved IF substitution technique wherein the IF test signal is applied to a feedback loop which generates a feedback signal to null out the test signal.
Abstract: Insertion loss measurement at microwave frequencies is achieved using an improved IF substitution technique wherein the IF test signal is applied to a feedback loop which generates a feedback signal to null out the test signal. A precision calibrated attenuator in the path of the feedback signal is adjusted to achieve the null, and the difference between attenuator settings with the device under test in and out of the microwave test signal path is a measure of the insertion loss of the device under test. In one embodiment the difference signal between the IF test signal and the fed back null signal is divided into amplitude and phase components which are integrated and used to control the attenuation and phase shift, respectively, of a reference signal at the IF test signal frequency, the controlled reference signal comprising the fed back null signal. In another embodiment the amplitude and phase components are filtered at d.c., restored to IF, and recombined before being fed back as the null signal. Still another embodiment steps the difference signal is stepped down to the audio frequency range in successive steps and is filtered at the audio level before being stepped back up to IF and fed back. Any of these embodiments can be employed in a dual channel system, one of which contains the device under test, wherein the fed back null signals are compared in phase to determine the phase shift introduced by the device under test. A novel phase shifter is disclosed wherein the 360° limitation of unambiguous phase detection is overcome.
TL;DR: In this paper, the insertion loss due to radiation curved dielectric image lines of rectangular cross section was measured for the frequency range from 26 to 90 GHz and a minimum acceptable curvature radius as a function of the frequency was calculated employing the field distributions of straight dielectrics image lines and is compared with measurements.
Abstract: Measurements of the insertion loss due to radiation curved dielectric image lines of rectangular cross section are described for the frequency range from 26 to 90 GHz. A minimum acceptable curvature radius as a function of the frequency is calculated employing the field distributions of straight dielectric image lines and is compared with measurements.
TL;DR: In this article, a new optical technique for servo tuning and stabilization of angle-tuned nonlinear optical crystals is described, which has zero insertion loss and works equally well with collimated, focused, or noncollinear fundamental beams.
Abstract: A new optical technique for servo tuning and stabilization of angle tuned nonlinear optical crystals is described. This technique has zero insertion loss and works equally well with collimated, focused, or noncollinear fundamental beams. Servo tuning of a Type I KDP nonlinear crystal for summing the output of a tunable dye laser with the Nd:YAG second harmonic and servo stabilization of the production of the Nd:YAG fourth harmonic in Type I KDP are demonstrated.
TL;DR: In this paper, a broadband resonant filter of up to 6% with an insertion loss under 3 dB was developed using a surface shear wave mode on an LiNbO3 Y-X substrate.
Abstract: A broadband resonant filter of a fractional bandwidth of up to 6% with an insertion loss under 3 dB has recently been developed using a surface shear wave mode on an LiNbO3 Y-X substrate. The filter is realised on a substrate with thin metal electrodes, comprising a twin-turn reflector (two 3 dB multistrip couplers and four reflectors) and two interdigital transducers, without using additional matching inductors.
Patent•
02 Mar 1979TL;DR: In this article, a broadband optical diode consisting of a Faraday element within a magnetic field and an optically active element was constructed with the conditions that the forward wave insertion loss does not exceed a maximum specified value, and the differential loss between forward and backward traveling waves is not less than a minimum specified value.
Abstract: A broadband optical diode consists of a Faraday element within a magnetic field and an optically active element. The materials and dimensions of the Faraday element and the optically active element are chosen so that their polarization rotations approximately match over a broad wavelength span, with the rotation angles and the mismatch between them specified by the conditions that the forward wave insertion loss does not exceed a maximum specified value, and the differential loss between forward and backward traveling waves is not less than a minimum specified value.