Pub Date : 1995-04-28DOI: 10.1109/SARNOF.1995.636702
C.E. Buchinsky, A. Katz
The ability to sharply limit power level while maintaining a negligible change in phase is important in many wireless communications systems. This paper investigates the use of a passive MESFET device as a power limiter for the UHF and lower microwave frequency range. The S-parameters of a commercial grade GaAs FET were measured as a function of power level and used to develop a model. From the model a limiter circuit was designed, fabricated and tested. The resulting limiter employed two FETs in cascade, and produced a near ideal transfer characteristic over more than a two decade power range with less than a 15 degree change in phase.
{"title":"Passive MESFET Limiters For Wireless Applications","authors":"C.E. Buchinsky, A. Katz","doi":"10.1109/SARNOF.1995.636702","DOIUrl":"https://doi.org/10.1109/SARNOF.1995.636702","url":null,"abstract":"The ability to sharply limit power level while maintaining a negligible change in phase is important in many wireless communications systems. This paper investigates the use of a passive MESFET device as a power limiter for the UHF and lower microwave frequency range. The S-parameters of a commercial grade GaAs FET were measured as a function of power level and used to develop a model. From the model a limiter circuit was designed, fabricated and tested. The resulting limiter employed two FETs in cascade, and produced a near ideal transfer characteristic over more than a two decade power range with less than a 15 degree change in phase.","PeriodicalId":118150,"journal":{"name":"IEEE Princeton Section Sarnoff Symposium","volume":"71 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121671438","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1995-04-28DOI: 10.1109/SARNOF.1995.636712
M. S. Heutmaker, L.M. Fletcher, J. E. Sohn
A microstrip directional coupler is used as a test circuit to measure the stray' capacitance and inductance due to solder flux residue deposits and solder joint geometry variations at frequencies up to 4.8 GHz. The stray capacitance is less than 50 femtofarads, and the absolute value of the stray inductance is less than 100 picohenries.
{"title":"Measurement of stray capacitance and inductance due to assembly variations in radio frequency circuit boards","authors":"M. S. Heutmaker, L.M. Fletcher, J. E. Sohn","doi":"10.1109/SARNOF.1995.636712","DOIUrl":"https://doi.org/10.1109/SARNOF.1995.636712","url":null,"abstract":"A microstrip directional coupler is used as a test circuit to measure the stray' capacitance and inductance due to solder flux residue deposits and solder joint geometry variations at frequencies up to 4.8 GHz. The stray capacitance is less than 50 femtofarads, and the absolute value of the stray inductance is less than 100 picohenries.","PeriodicalId":118150,"journal":{"name":"IEEE Princeton Section Sarnoff Symposium","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132015044","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1995-04-28DOI: 10.1109/SARNOF.1995.636751
B. Nyman, S.G. Evangelizes
The large gain bandwidth of erbium doped fiber amplifiers has stimulated interest in WDM systems with many channels. For trans-oceanic and other such long-haul systems, the number of channels is limited by the accumulated gain bandwidth, which tends to decrease rapidly with distance. For NRZ systems, additional limitations arise from four wave mixing among the channels. Soliton transmission reduces these problems and allows for greatly reduced channel spacing. In particular, in recent experiment the adjacent channel spacing was just 25 GHz, or ~0.2 nm. The main sources of limitations in soliton systems are timing jitter and amplitude noise In WDM systems there is an additional contribution to the timing jitter from interactions between channels. Here, we examine the limitations of soliton WDM systems.
{"title":"Soliton WDM transmission","authors":"B. Nyman, S.G. Evangelizes","doi":"10.1109/SARNOF.1995.636751","DOIUrl":"https://doi.org/10.1109/SARNOF.1995.636751","url":null,"abstract":"The large gain bandwidth of erbium doped fiber amplifiers has stimulated interest in WDM systems with many channels. For trans-oceanic and other such long-haul systems, the number of channels is limited by the accumulated gain bandwidth, which tends to decrease rapidly with distance. For NRZ systems, additional limitations arise from four wave mixing among the channels. Soliton transmission reduces these problems and allows for greatly reduced channel spacing. In particular, in recent experiment the adjacent channel spacing was just 25 GHz, or ~0.2 nm. The main sources of limitations in soliton systems are timing jitter and amplitude noise In WDM systems there is an additional contribution to the timing jitter from interactions between channels. Here, we examine the limitations of soliton WDM systems.","PeriodicalId":118150,"journal":{"name":"IEEE Princeton Section Sarnoff Symposium","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133496442","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1995-04-28DOI: 10.1109/SARNOF.1995.636767
P. Heim, S. Merritt, Z. Fan, M. Dagenais, R. Leavitt
A tunable 980 nm external cavity laser based upon a single-angled-facet (SAF) semiconductor laser diode is demonstrated that does not require anti-reflection coatings or additional external mirrors. The SAF laser diode is comprised of a curved ridge waveguide that intersects the facet cleavage plane normally at one facet and at an angle at the other facet. A wide tuning range (70 nm) external cavity laser was obtained by coupling the output from the low reflectivity angled facet (R = 2 x 10-5) to a diffraction grating.
{"title":"Single-angled-facet laser diode for tunable external cavity lasers","authors":"P. Heim, S. Merritt, Z. Fan, M. Dagenais, R. Leavitt","doi":"10.1109/SARNOF.1995.636767","DOIUrl":"https://doi.org/10.1109/SARNOF.1995.636767","url":null,"abstract":"A tunable 980 nm external cavity laser based upon a single-angled-facet (SAF) semiconductor laser diode is demonstrated that does not require anti-reflection coatings or additional external mirrors. The SAF laser diode is comprised of a curved ridge waveguide that intersects the facet cleavage plane normally at one facet and at an angle at the other facet. A wide tuning range (70 nm) external cavity laser was obtained by coupling the output from the low reflectivity angled facet (R = 2 x 10-5) to a diffraction grating.","PeriodicalId":118150,"journal":{"name":"IEEE Princeton Section Sarnoff Symposium","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114437424","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1995-04-28DOI: 10.1109/SARNOF.1995.636720
V. Vusirikala, S. Cho, P. Heim, M. Dagenais, C. Wood
Due to gain saturation effects, the gaincurrent density curve in QW lasers is better approximated by a logarithmic than a linear curve. (Γg = G0 ln(ηi J/J0)). We report on the determination of the logarithmic gain coefficient (G0) for QW lasers, from single pass gain measurements. We show that G0 scales well with the number of quantum wells. These G0 values are compared with the values obtained from a logarithmic fit to the theoretical gain-current density curves. The temperature dependence of single pass gain is also investigated and was found to increase with G0.
{"title":"Measurement of logarithmic gain coefficient (G0) and temperature sensitivity in gaas/aigaas quantum well lasers","authors":"V. Vusirikala, S. Cho, P. Heim, M. Dagenais, C. Wood","doi":"10.1109/SARNOF.1995.636720","DOIUrl":"https://doi.org/10.1109/SARNOF.1995.636720","url":null,"abstract":"Due to gain saturation effects, the gaincurrent density curve in QW lasers is better approximated by a logarithmic than a linear curve. (Γg = G<sub>0</sub> ln(ηi J/J<sub>0</sub>)). We report on the determination of the logarithmic gain coefficient (G<sub>0</sub>) for QW lasers, from single pass gain measurements. We show that G<sub>0</sub> scales well with the number of quantum wells. These G<sub>0</sub> values are compared with the values obtained from a logarithmic fit to the theoretical gain-current density curves. The temperature dependence of single pass gain is also investigated and was found to increase with G<sub>0</sub>.","PeriodicalId":118150,"journal":{"name":"IEEE Princeton Section Sarnoff Symposium","volume":"121 44","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120818836","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1995-04-28DOI: 10.1109/SARNOF.1995.636707
R. Qiu, I. Lu
The conventional complex channel model for wireless indoor propagation is extended to include the frequency dependence of individual rays. Multiple ray paths are resolved using high-resolution digital signal processing algorithms. The Cramer - Rao bound is used as a benchmark where a newly developed modified eigen-matrix pencil method is proven to be most successful.
{"title":"A novel high-reslolution algorithm for ray path resolving and wireless channel modelling","authors":"R. Qiu, I. Lu","doi":"10.1109/SARNOF.1995.636707","DOIUrl":"https://doi.org/10.1109/SARNOF.1995.636707","url":null,"abstract":"The conventional complex channel model for wireless indoor propagation is extended to include the frequency dependence of individual rays. Multiple ray paths are resolved using high-resolution digital signal processing algorithms. The Cramer - Rao bound is used as a benchmark where a newly developed modified eigen-matrix pencil method is proven to be most successful.","PeriodicalId":118150,"journal":{"name":"IEEE Princeton Section Sarnoff Symposium","volume":"141-142 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117172398","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1995-04-28DOI: 10.1109/SARNOF.1995.636675
D. Helms
PHEMTs, grown on GaAs and InP, due to their extremely high mobility, offer significant performance advantages from UHF to W-band: the lowest noise figures at the highest gains and very high power at the highest efficiencies. These performance improvements enable the development of major advances in systems applications. This presentation compares PHEMTs to MESFETs to show how each works and points out the advantages of using PHEMTs for systems applications.
{"title":"PHEMTs - Emerging High Performance Devices","authors":"D. Helms","doi":"10.1109/SARNOF.1995.636675","DOIUrl":"https://doi.org/10.1109/SARNOF.1995.636675","url":null,"abstract":"PHEMTs, grown on GaAs and InP, due to their extremely high mobility, offer significant performance advantages from UHF to W-band: the lowest noise figures at the highest gains and very high power at the highest efficiencies. These performance improvements enable the development of major advances in systems applications. This presentation compares PHEMTs to MESFETs to show how each works and points out the advantages of using PHEMTs for systems applications.","PeriodicalId":118150,"journal":{"name":"IEEE Princeton Section Sarnoff Symposium","volume":"104 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123657158","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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