Dual Output Laser Module for a Tunable Laser Source

This reliable, hermetically sealed laser module is a key component in the HP 8167A and HP 8168A tunable laser sources. The semiconductor laser chip is precisely and stably aligned to two output lenses. One facet of the laser chip is antireflection-coated and has very low residual reflectivity, by Roger L. Jungermait, David M. Braun, and Kari K. Salomaa Wavel en gth-t unable light sources in the near-infrared wavelength band of 1300 to 1550 tun are finding increasing use in fiberoptic...

Design of a Precision Optical Low Coherence Reflectometer

The HP 8504A precision reflectometer uses the classic Michelson interferometric measurement technique to allow designers and manufacturers to measure reflections easily in optical components and assemblies. Spatial resolution is on the order of tens of micrometers. by D. Howard Booster. Harry Chou, Michael G. Hart, Steven J. Mifsud, and Rollin F. Rawson An optical low-coherence reflectometer uses a Micholson interferometer configured with a broadband source to make spatially resolved...

Characterization Toots

Two important characterization tools made possible the development of the photonics devices mentioned in this article. The first, is photoluminescence and the second is elect.rooptie sampling. Photoluminescence (continuous wave and time-resolved) is used to characterize III-V compound semiconductor epitaxial films and is crucial to the development of high-quality films. For example, Fig, 5 shows time-resolved photo luminescence from AlGalnP structures for live excitation energies. The...

By Harry Chou and Wayne V Sorin

Reflections in optical components and systems often pose problems to the designer. For example, many laser sources become unstable when laser light is reflected back into the laser cavity. These reflections can cause abrupt frequency changes or increased inlensity noise, even for reflectivities ls low as l() y (-80 dB). Therefore, it is necessary for laser manufacturers to avoid any excess reflections within their laser packages. Reflecting surfaces can also set up optical resonances known as...

K

See Averaging Measurements to Improve Sensitivity, on page 44 for more about measurement averaging. Calibration processes are used io remove systematic measurement errors and to reference measurements l o a reflection of known magnitude. The calibration process consists of several steps. First the de offsets in the receiver channels are measured. Next , with a low-reflection termination connected to the lest port, the receiver polarization is balanced to divide the reference power equally...

Tunable Laser Sources for Optical Amplifier Testing

Two models of laser sources tune over wavelength ranges of 50 and 65 nanometers using grating-tuned external-cavity lasers with precisely controlled wavelength and power level. They are designed for testing wideband components such as erbium-doped fiber amplifiers. by Bernd Maisenbacher, Edgar Leckel, Robert Jahii, and Michael Pott Recently there has been greal merest in using erbium-doped fiber amplifiers EDFAs as repeaters in lightwave transmission systems. These optical amplifiers are...

Improving SNR by Averaging

Signal averaging in OTDHs sums repetitions of measurement shots using an accurate time reference for synchronisation To see haw averaging imptoves signalto-ffljrse ratio ISNfll we represent a ngle shot measurement tesult r, t as a Signal part sftl sndan uncorretated noise element alt - The sum ravg t of N repetitive measurement shots divided by N is It can be seen that the correlated signal parts sit add up proportionally, but the raise sum needs more detailed consideration. Ths rms noise level...

Photonic Technology for Lightwave Communications Test Applications

State-of-the-art fiber-optic, integrated-optic, bulk-optic, and optoelectronic devices and subsystems provide a technology base for high-speed, high-performance lightwave communications test instrumentation. by Waguih S. Ishak, Kent W. Carey, Steven A. Newton, and William R. TVutna, Jr. The fiber-op amp e systemsthat emerged during the decade of the 1980s have revolutionised high-speed communications by competing very well with more traditional systems as cost-effective means for information...

By Josef BeJIcr and Wilfried Pless

Fiber optics has long been estabJished in I he communication world and ho have the test louls that, measure and characterize the equipment needed for fiber-optic transmission. Some of these test tools includes Highly accurate power meters lo measure the output, power of transmitters Optical sources laser or LEIJ to st imulate transmitters Power meters and sources to characterize passive optical devices Optical spectrum analyzers to measure the wavelength of optica sources Return loss meters to...

By David J McQuate Kok Wai Chang and Christopher J Madden

The UP 83450 Series lightwave detectors described in the article on page 83 are a family of optical-to-electrical converters that includes models with bandwidths above 20 GHz. To test and calibrate these detectors, a higher-frequency test system was required. In this article we describe three systems that can be used to characterize high-speed lightwave converters. The first is a time-domain system thai measures a photo receiver's response to a short optical pnl.se. In the second system, two...

February

Egypt and attended H r universities in Egypt and M -J Canada before joining HP H' T lb Laboratories in 197B He L V-J 3N received a BSc degree in -J I, electrical engine Bring from J j_ Cairo Unmersity in 1971 and a BSc degree in mathematics from Am Shams University itl '973. His MSc and PhD degrees in electrical engineering were awarded by Mc Master University m 1975 and 1978. Al HP. lie designed surface acoustic wave lew-loss filters for several products...

External Cavity Laser Design and Wavelength Calibration

Sophisticated tuning and calibration methods coordinate the effects of a diffraction grating wavelength selector and a Fabry-Perot etalon side-mode suppression filter to ensure accurate wavelength selection and single-mode operation in the HP 8167A and 8168A tunable laser sources. by Emmeric h M ller, Wolfgang Reichert, Clemens Riick, and Rolf Steiner To achieve the required tuning performance for the HP 8167A and 8168A tunable laser sources, 1 was decided to develop a tunable laser hased on a...

Analyzing OTDR Traces on a PC with a Windows User Interface

One of the tasks that is important to OTDR users is ttie aii11 ty tn save measurement remits on su'table media and to compare results from different measurement sessions With this capability, users can obtain information about Ifie eging of ftders. observe the effects of bending fibers very early, and do all tiie statistics That are relevant for evaluating the quality of the transmission link Besides offering printers for documenting and savng measurement results, there needs to tie software...

OTDR Software

The binary code for revision 1.0 of the OTDR software is almost 500K bytes. The software runs on a Motorola 68010 microprocessor and is based on the real-time multiprocessing operating system pSOS-OBk, which can coordinate multiple asynchronous activities. Thus, we have six independent processes running in parallel. Each process has its own data area and stack. A process communicates with others by sending signals or messages via the operating system. Information common to multiple processes is...

External Cavity Laser Temperature Stabilization and Power Control

The theory and operation of the laser temperature control and measurement circuits and the output power control and calibration of the HP 8167A 68A tunable laser sources are presented. by Horst Schweikardt and Edgar Lecke Tile operating temperature of the external-cavity laser of tiie HP8167A and 8168A tunable laser sources is from 5 C to 3ir'C, To meet instrument specifications over this temperature range it is necessary to stabilize the temperature of the key internal components. The simplest...