Pub Date : 1990-07-23DOI: 10.1109/BAODS.1990.205515
K. Lau
Summary form only given. Developments in high-speed semiconductor lasers have made possible the practical realization of optical/microwave systems as exemplified by applications such as antenna remoting, delay lines, and optically steerable phased-array antennas, to name a few. Present-day laser diodes can attain direct modulation bandwidths of up to 20 GHz. To advance into the higher-frequency and millimeter-wave range, lasers incorporating quantum-well structures should be used. This structure is largely if not solely responsible for recent advances in obtaining ultralow lasing threshold (0.5 mA), ultrahigh modulation speed (30 GHz), and ultrahigh AM and FM modulation efficiency. Recent theoretical predictions and experimental demonstrations also showed that appropriately designed single-quantum-well lasers can be made to mode-lock at millimeter-wave frequencies of 100 GHz or higher. Furthermore, the introduction of strained-layer quantum-well structures has furthered these goals. They will have significant implications not only in the establishment of optical techniques in microwave and radar systems, but also in computer optical interconnects and in telecommunications.<>
{"title":"Quantum well lasers for microwave/millimeter wave applications","authors":"K. Lau","doi":"10.1109/BAODS.1990.205515","DOIUrl":"https://doi.org/10.1109/BAODS.1990.205515","url":null,"abstract":"Summary form only given. Developments in high-speed semiconductor lasers have made possible the practical realization of optical/microwave systems as exemplified by applications such as antenna remoting, delay lines, and optically steerable phased-array antennas, to name a few. Present-day laser diodes can attain direct modulation bandwidths of up to 20 GHz. To advance into the higher-frequency and millimeter-wave range, lasers incorporating quantum-well structures should be used. This structure is largely if not solely responsible for recent advances in obtaining ultralow lasing threshold (0.5 mA), ultrahigh modulation speed (30 GHz), and ultrahigh AM and FM modulation efficiency. Recent theoretical predictions and experimental demonstrations also showed that appropriately designed single-quantum-well lasers can be made to mode-lock at millimeter-wave frequencies of 100 GHz or higher. Furthermore, the introduction of strained-layer quantum-well structures has furthered these goals. They will have significant implications not only in the establishment of optical techniques in microwave and radar systems, but also in computer optical interconnects and in telecommunications.<<ETX>>","PeriodicalId":119716,"journal":{"name":"LEOS Summer Topical on Broadband Analog Optoelectronics: Devices and Systems","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127365114","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 : 1990-07-23DOI: 10.1109/BAODS.1990.205490
R. Olshansky
Applications for lightwave baseband systems operating at data rates above 4-5 Gb/s are limited, primarily because of the limited availability of high-speed digital circuits, high cost, and the difficulty of working with digital electronics at this data rate. Subcarrier multiplexing (SCM) provides a way to free lightwave system bandwidth from the limitations imposed by digital electronics and offers all alternative approach for exploiting the many gigahertz of available bandwidth. SCM allows the system designer to work with almost the entire range of available electronics at either RF or microwave frequencies. It also allows the use of a wide variety of signaling formats, including AM, FM, ASK, FSK, BPSK, and QPSK. The full range of lightwave techniques, including all wideband electrooptic components. WDM techniques, optical amplification, and coherent detection can be exploited. The compatibility of SCM with digital technology and time-division multiplexing (TDM) is also recognized.<>
{"title":"Overview of broadband SCM systems","authors":"R. Olshansky","doi":"10.1109/BAODS.1990.205490","DOIUrl":"https://doi.org/10.1109/BAODS.1990.205490","url":null,"abstract":"Applications for lightwave baseband systems operating at data rates above 4-5 Gb/s are limited, primarily because of the limited availability of high-speed digital circuits, high cost, and the difficulty of working with digital electronics at this data rate. Subcarrier multiplexing (SCM) provides a way to free lightwave system bandwidth from the limitations imposed by digital electronics and offers all alternative approach for exploiting the many gigahertz of available bandwidth. SCM allows the system designer to work with almost the entire range of available electronics at either RF or microwave frequencies. It also allows the use of a wide variety of signaling formats, including AM, FM, ASK, FSK, BPSK, and QPSK. The full range of lightwave techniques, including all wideband electrooptic components. WDM techniques, optical amplification, and coherent detection can be exploited. The compatibility of SCM with digital technology and time-division multiplexing (TDM) is also recognized.<<ETX>>","PeriodicalId":119716,"journal":{"name":"LEOS Summer Topical on Broadband Analog Optoelectronics: Devices and Systems","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122442949","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 : 1990-07-23DOI: 10.1109/BAODS.1990.205503
L. Johnson, H. Roussell
The linearization of all interferometric modulator by polarization mixing over the suboctave frequency range of 3.6 to 5.6 GHz is reported. A traveling-wave modulator fabricated in X-cut LiNbO/sub 3/ utilizing the r/sub 33/ (TE) and r/sub 13/ (TM) electrooptic coefficients was employed. The effective V/sub pi /s (from a 50- Omega source) were 14 and 43 V for the TE and TM modes, respectively. The modulator response was not optimized for this frequency range. A DC voltage was used to separate bias electrodes to adjust the relative TE and TM phase bias. A polarizer was placed between the diode-pumped Nd:YAG laser source, and the modulator to adjust the relative TE and TM optical power. The modulator output was measured with a high-speed photodetector and spectrum analyzer.<>
{"title":"Linearization of an interferometric modulator at microwave frequencies by polarization mixing","authors":"L. Johnson, H. Roussell","doi":"10.1109/BAODS.1990.205503","DOIUrl":"https://doi.org/10.1109/BAODS.1990.205503","url":null,"abstract":"The linearization of all interferometric modulator by polarization mixing over the suboctave frequency range of 3.6 to 5.6 GHz is reported. A traveling-wave modulator fabricated in X-cut LiNbO/sub 3/ utilizing the r/sub 33/ (TE) and r/sub 13/ (TM) electrooptic coefficients was employed. The effective V/sub pi /s (from a 50- Omega source) were 14 and 43 V for the TE and TM modes, respectively. The modulator response was not optimized for this frequency range. A DC voltage was used to separate bias electrodes to adjust the relative TE and TM phase bias. A polarizer was placed between the diode-pumped Nd:YAG laser source, and the modulator to adjust the relative TE and TM optical power. The modulator output was measured with a high-speed photodetector and spectrum analyzer.<<ETX>>","PeriodicalId":119716,"journal":{"name":"LEOS Summer Topical on Broadband Analog Optoelectronics: Devices and Systems","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115429072","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 : 1990-07-23DOI: 10.1109/BAODS.1990.205518
C. Ih, X.L. Wang, R. Tian, W. Gu
A FM modulated frequency-locked laser (FLL) pair for optical communication is reported. The subcarrier (locked) frequencies can be easily tuned from 3 to 11 GHz. Utilizing the FLL modulator within its bandwidth limits, any broadband analog signal, such as TV VHF bands (lower and upper band plus FM radio), CATV channels, and even TV UHF band, can be readily FM modulated on to these very-high-frequency microwave subcarriers. A simple FM demodulation can then be used to recover the original signals. This is directly compatible with standard TV or cable-ready receivers. Digital data in Manchester code format can also be transmitted. The operation of the FLL and the transmission and reception of five TV channels (channels 2 to 6 or substituting one with channel 13) on a 11-GHz subcarrier were experimentally demonstrated. The FLL is based on the concept of double beam modulation (DBM), which can be readily utilized for subcarrier modulated (SCM) multichannel broadband communications.<>
{"title":"11 GHz SCM broadband communications using frequency-locked lasers","authors":"C. Ih, X.L. Wang, R. Tian, W. Gu","doi":"10.1109/BAODS.1990.205518","DOIUrl":"https://doi.org/10.1109/BAODS.1990.205518","url":null,"abstract":"A FM modulated frequency-locked laser (FLL) pair for optical communication is reported. The subcarrier (locked) frequencies can be easily tuned from 3 to 11 GHz. Utilizing the FLL modulator within its bandwidth limits, any broadband analog signal, such as TV VHF bands (lower and upper band plus FM radio), CATV channels, and even TV UHF band, can be readily FM modulated on to these very-high-frequency microwave subcarriers. A simple FM demodulation can then be used to recover the original signals. This is directly compatible with standard TV or cable-ready receivers. Digital data in Manchester code format can also be transmitted. The operation of the FLL and the transmission and reception of five TV channels (channels 2 to 6 or substituting one with channel 13) on a 11-GHz subcarrier were experimentally demonstrated. The FLL is based on the concept of double beam modulation (DBM), which can be readily utilized for subcarrier modulated (SCM) multichannel broadband communications.<<ETX>>","PeriodicalId":119716,"journal":{"name":"LEOS Summer Topical on Broadband Analog Optoelectronics: Devices and Systems","volume":"71 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124137131","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 : 1990-07-23DOI: 10.1109/BAODS.1990.205517
M. Majewski
The relationship between the optical signal response at the fundamental modulation frequency and the magnitude of the driving current is of particular importance to analog communication applications of semiconductor laser diodes. A closed-form analytical expression for the optical response of a laser diode under large-signal direct modulation conditions is presented. It was derived on the basis of the single-mode rate equations. The rate equations used in the analysis presented include the optical gain compression term. It was found that the magnitude of the gain compression ( in ) strongly affects the linearity of the large-signal modulation characteristic, particularly at higher modulation frequencies close to the frequency of the relaxation oscillation peak. The relaxation oscillation peak whose magnitude depends on the value of in exhibits a shift towards lower frequencies with the increase of electrical modulation depth.<>
{"title":"Nonlinear effects associated with the large-signal direct modulation of semiconductor laser diodes","authors":"M. Majewski","doi":"10.1109/BAODS.1990.205517","DOIUrl":"https://doi.org/10.1109/BAODS.1990.205517","url":null,"abstract":"The relationship between the optical signal response at the fundamental modulation frequency and the magnitude of the driving current is of particular importance to analog communication applications of semiconductor laser diodes. A closed-form analytical expression for the optical response of a laser diode under large-signal direct modulation conditions is presented. It was derived on the basis of the single-mode rate equations. The rate equations used in the analysis presented include the optical gain compression term. It was found that the magnitude of the gain compression ( in ) strongly affects the linearity of the large-signal modulation characteristic, particularly at higher modulation frequencies close to the frequency of the relaxation oscillation peak. The relaxation oscillation peak whose magnitude depends on the value of in exhibits a shift towards lower frequencies with the increase of electrical modulation depth.<<ETX>>","PeriodicalId":119716,"journal":{"name":"LEOS Summer Topical on Broadband Analog Optoelectronics: Devices and Systems","volume":"73 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114835941","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 : 1990-07-23DOI: 10.1109/BAODS.1990.205506
J. A. Chiddix
The tree-and-branch architecture of today's cable television systems is optimized for broadband, broadcast video delivery. A key characteristic of coaxial cable is its relatively high transmission loss, about 1 dB per 100 ft at 550 MHz. The advent of low-cost, single-mode optical fiber and broadband analog optoelectronic devices allows the constructions of hybrid fiber/coaxial systems where fiber is used for trunking over relatively long distances, and coaxial cable is used for 'the last mile' to the home. This approach of overlaying an existing coaxial system with fiber trunking is referred to as fiber backbone. The integration of the fiber backbone structure into existing CATV systems allows a dramatic increase in system reliability, delivery signal quality, and channel capacity. Fiber backbone is also the first step in an evolution to a cost-effective, two-way communications system, ultimately capable of delivering switched video services on demand to the consumer.<>
{"title":"The integration of optical fiber into today's cable television networks","authors":"J. A. Chiddix","doi":"10.1109/BAODS.1990.205506","DOIUrl":"https://doi.org/10.1109/BAODS.1990.205506","url":null,"abstract":"The tree-and-branch architecture of today's cable television systems is optimized for broadband, broadcast video delivery. A key characteristic of coaxial cable is its relatively high transmission loss, about 1 dB per 100 ft at 550 MHz. The advent of low-cost, single-mode optical fiber and broadband analog optoelectronic devices allows the constructions of hybrid fiber/coaxial systems where fiber is used for trunking over relatively long distances, and coaxial cable is used for 'the last mile' to the home. This approach of overlaying an existing coaxial system with fiber trunking is referred to as fiber backbone. The integration of the fiber backbone structure into existing CATV systems allows a dramatic increase in system reliability, delivery signal quality, and channel capacity. Fiber backbone is also the first step in an evolution to a cost-effective, two-way communications system, ultimately capable of delivering switched video services on demand to the consumer.<<ETX>>","PeriodicalId":119716,"journal":{"name":"LEOS Summer Topical on Broadband Analog Optoelectronics: Devices and Systems","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129280390","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 : 1990-07-23DOI: 10.1109/BAODS.1990.205497
R. Murphy
An AM fiber-optic distribution system developed for the Deutsche Bundespost of the Federal Republic of Germany is described. This is the first deployed video system utilizing Raynet noninvasive coupler technology supplying PAL format video and FM audio in the subscriber loop. The optical transport consists of connectors, single-mode optical fibers, splices, and noninvasive optical couplers providing a bus architecture for the transportation of intensity modulated (IM) AM video. Subscriber interface units (SIUs) are connected to the bus either via noninvasive couplers or directly at the end of a fiber.<>
{"title":"AM fiber-optic local loop distribution in Cologne, West Germany","authors":"R. Murphy","doi":"10.1109/BAODS.1990.205497","DOIUrl":"https://doi.org/10.1109/BAODS.1990.205497","url":null,"abstract":"An AM fiber-optic distribution system developed for the Deutsche Bundespost of the Federal Republic of Germany is described. This is the first deployed video system utilizing Raynet noninvasive coupler technology supplying PAL format video and FM audio in the subscriber loop. The optical transport consists of connectors, single-mode optical fibers, splices, and noninvasive optical couplers providing a bus architecture for the transportation of intensity modulated (IM) AM video. Subscriber interface units (SIUs) are connected to the bus either via noninvasive couplers or directly at the end of a fiber.<<ETX>>","PeriodicalId":119716,"journal":{"name":"LEOS Summer Topical on Broadband Analog Optoelectronics: Devices and Systems","volume":"44 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121378513","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 : 1990-07-23DOI: 10.1109/BAODS.1990.205499
J. Farina, F. Leonberger
External modulation, using integrated optics (IO) modulators, has recently received attention in analog fiber system applications. This focus is due to the availability of linear modulators capable of operating at the high optical powers now available from high-power CW diode and diode-pumped sources. Broadband high-dynamic-range fiber optic links based on integrated optic modulators show great promise for application in antenna remoting and RF signal distribution, such as in CATV networks. Some of the recent advances in these devices and their applications are briefly outlined. Advances in IO modulator technology have occurred in several areas. High-dynamic-range results have been achieved at RF frequencies in a number of LiNbO/sub 3/ modulator structures, including Mach-Zehnder, directional coupler, and synchronous directional couplers.<>
{"title":"Overview of applications of external modulation","authors":"J. Farina, F. Leonberger","doi":"10.1109/BAODS.1990.205499","DOIUrl":"https://doi.org/10.1109/BAODS.1990.205499","url":null,"abstract":"External modulation, using integrated optics (IO) modulators, has recently received attention in analog fiber system applications. This focus is due to the availability of linear modulators capable of operating at the high optical powers now available from high-power CW diode and diode-pumped sources. Broadband high-dynamic-range fiber optic links based on integrated optic modulators show great promise for application in antenna remoting and RF signal distribution, such as in CATV networks. Some of the recent advances in these devices and their applications are briefly outlined. Advances in IO modulator technology have occurred in several areas. High-dynamic-range results have been achieved at RF frequencies in a number of LiNbO/sub 3/ modulator structures, including Mach-Zehnder, directional coupler, and synchronous directional couplers.<<ETX>>","PeriodicalId":119716,"journal":{"name":"LEOS Summer Topical on Broadband Analog Optoelectronics: Devices and Systems","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133570224","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 : 1990-07-23DOI: 10.1109/BAODS.1990.205496
S. Huang, T. W. Cline, L.C. Upadhyayula, R. Tench, J. Lipson, J. Simpson
It is demonstrated that an erbium-doped fiber amplifier (EDFA) can be successfully used as a power amplifier for point-to-multipoint distributions of 42-channel VSB-AM video signals. The amplifier has a 31.4-dB net small-signal gain and 6.1-dBm saturated power. When used as a power amplifier, the EDFA is heavily saturated with a 19.2-dB gain compression and 12.2-dBm output power. The total optical power budget is 20 dB at CNR of 50 dB. Both composite-triple-bit and composite-second-order distortions after the amplifier and splitter are about or above 60 dBc. The possibility of cascading these fiber amplifiers and branching their outputs makes them well suited for tree-and-branch-like CATV distribution systems.<>
{"title":"Point-to-multipoint distributions of 42 channel VSB-AM video signals using an erbium-doped fiber amplifier","authors":"S. Huang, T. W. Cline, L.C. Upadhyayula, R. Tench, J. Lipson, J. Simpson","doi":"10.1109/BAODS.1990.205496","DOIUrl":"https://doi.org/10.1109/BAODS.1990.205496","url":null,"abstract":"It is demonstrated that an erbium-doped fiber amplifier (EDFA) can be successfully used as a power amplifier for point-to-multipoint distributions of 42-channel VSB-AM video signals. The amplifier has a 31.4-dB net small-signal gain and 6.1-dBm saturated power. When used as a power amplifier, the EDFA is heavily saturated with a 19.2-dB gain compression and 12.2-dBm output power. The total optical power budget is 20 dB at CNR of 50 dB. Both composite-triple-bit and composite-second-order distortions after the amplifier and splitter are about or above 60 dBc. The possibility of cascading these fiber amplifiers and branching their outputs makes them well suited for tree-and-branch-like CATV distribution systems.<<ETX>>","PeriodicalId":119716,"journal":{"name":"LEOS Summer Topical on Broadband Analog Optoelectronics: Devices and Systems","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131868163","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 : 1990-07-23DOI: 10.1109/BAODS.1990.205492
S. Liew
A novel optical network based on wavelength-division-multiplexing (WDM) and subcarrier-multiplexing (SCM) technologies is proposed that allows support of multiple service vendors on a common distribution infrastructure. At the central office, wavelengths lambda /sub 1/ to lambda /sub 8/, which carry switched information streams to eight separate subscribers, are multiplexed optically onto one optical fiber. Another eight distinct wavelengths, lambda /sub 9/ to lambda /sub 16/, are used to carry the broadcast video channels of eight video vendors to the subscribers. The signals on the eight video wavelengths are combined and split 128 ways using all 8*128 asymmetric star coupler. Each of the 128 outputs is associated with a set of eight subscribers, and each output is combined with the output of an associated WDM device through a coupler. Thus, each video source supports a total of 128*8=1024 subscribers. An optical amplifier is used to boost the combined signals.<>
{"title":"A multivendor multiservice local network based on wavelength-division multiplexing and subcarrier multiplexing","authors":"S. Liew","doi":"10.1109/BAODS.1990.205492","DOIUrl":"https://doi.org/10.1109/BAODS.1990.205492","url":null,"abstract":"A novel optical network based on wavelength-division-multiplexing (WDM) and subcarrier-multiplexing (SCM) technologies is proposed that allows support of multiple service vendors on a common distribution infrastructure. At the central office, wavelengths lambda /sub 1/ to lambda /sub 8/, which carry switched information streams to eight separate subscribers, are multiplexed optically onto one optical fiber. Another eight distinct wavelengths, lambda /sub 9/ to lambda /sub 16/, are used to carry the broadcast video channels of eight video vendors to the subscribers. The signals on the eight video wavelengths are combined and split 128 ways using all 8*128 asymmetric star coupler. Each of the 128 outputs is associated with a set of eight subscribers, and each output is combined with the output of an associated WDM device through a coupler. Thus, each video source supports a total of 128*8=1024 subscribers. An optical amplifier is used to boost the combined signals.<<ETX>>","PeriodicalId":119716,"journal":{"name":"LEOS Summer Topical on Broadband Analog Optoelectronics: Devices and Systems","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124578624","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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