Pub Date : 1995-04-28DOI: 10.1109/SARNOF.1995.636670
F. Ali
AlGaAs/GaAs Heterojunction Bipolar Transistors (HBTs) designed for microwave power applicatims have shown marked improvements in output power and power-added efficiency (PAE) during recent years. This paper provides a synopsis of the design considerations for high efficiency, GaAs HBT unit-cell and power amplifiers. Performance results of several high efficiency HBT power MMIC amplifiers designed for narrowband and broadband applications are also be presented.
{"title":"GaAs Power HBT: COOL Device With HOT Performance","authors":"F. Ali","doi":"10.1109/SARNOF.1995.636670","DOIUrl":"https://doi.org/10.1109/SARNOF.1995.636670","url":null,"abstract":"AlGaAs/GaAs Heterojunction Bipolar Transistors (HBTs) designed for microwave power applicatims have shown marked improvements in output power and power-added efficiency (PAE) during recent years. This paper provides a synopsis of the design considerations for high efficiency, GaAs HBT unit-cell and power amplifiers. Performance results of several high efficiency HBT power MMIC amplifiers designed for narrowband and broadband applications are also be presented.","PeriodicalId":118150,"journal":{"name":"IEEE Princeton Section Sarnoff Symposium","volume":"9 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":"122565550","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.1995.636716
A. Streater, J. A. Kleinfeld
We discuss theoretical and experimental investigations of gain phenomena and refractive index control in atomic systems due to coherences induced by a pump laser. Experimental results in potassium vapor are compared with 3-level and 4-level models.
{"title":"Optical gain and refractive index manipulation in coherently prepared atomic systems","authors":"A. Streater, J. A. Kleinfeld","doi":"10.1109/SARNOF.1995.636716","DOIUrl":"https://doi.org/10.1109/SARNOF.1995.636716","url":null,"abstract":"We discuss theoretical and experimental investigations of gain phenomena and refractive index control in atomic systems due to coherences induced by a pump laser. Experimental results in potassium vapor are compared with 3-level and 4-level models.","PeriodicalId":118150,"journal":{"name":"IEEE Princeton Section Sarnoff Symposium","volume":"3 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":"121500648","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.1995.636754
K. I. Kang, T. Chang, I. Glesk, P. Prucnal
Recent developments in all-optical switching devices based on the interferometric principle are very promising for optical communication systems, especially those based on optical time division multiplexing system (OTDM), where a user is allowed to transmit or receive a data in a assigned time slot within a given time frame. One such device based on a Sagnac interferometer is called a Terahertz Optical Asymmetric Demultiplexer (the TOAD). Another device based on a Mach-Zehnder interferometer is a Symmetric Mach-Zehnder (SMZ). Both devices utilize large optical nonlinearities in the resonance regime of the semiconductor, therefore it is possible to operate these devices with a very small optical control pulse energy. The currently demonstrated TOAD can be switched with 0.8 pJ, and the SMZ with 11 pJ. We still can reduce the control pulse energy by optimizing and employing other nonlinear optical materials. The most critical problem associated with a slow recovery time of the resonance nonlinearities has been solved by a special geometrical location of a nonlinear optical element in the Sagnac interferometer, and two control pulses to do independent on and off switching operation for the Mach-Zehnder. We demonstrated a 10 ps switching window by counter-propagating the control and data pulses in the Mach-Zehnder interferometer using 0.65 pJ of control pulse energy. This device is advantageous in its superior rejection capability of the control signal. In terms of the possibility of integration, this device is expected to be a much simpler design than the previously demonstrated systems. Also the utilized optical nonlinear elements are semiconductor optical amplifiers, the data signal can be larger than the input. This may facilitate cascadability and fan-out capability.
{"title":"Ultrafast all-optical wavelength and polarization independent demultiplexer","authors":"K. I. Kang, T. Chang, I. Glesk, P. Prucnal","doi":"10.1109/SARNOF.1995.636754","DOIUrl":"https://doi.org/10.1109/SARNOF.1995.636754","url":null,"abstract":"Recent developments in all-optical switching devices based on the interferometric principle are very promising for optical communication systems, especially those based on optical time division multiplexing system (OTDM), where a user is allowed to transmit or receive a data in a assigned time slot within a given time frame. One such device based on a Sagnac interferometer is called a Terahertz Optical Asymmetric Demultiplexer (the TOAD). Another device based on a Mach-Zehnder interferometer is a Symmetric Mach-Zehnder (SMZ). Both devices utilize large optical nonlinearities in the resonance regime of the semiconductor, therefore it is possible to operate these devices with a very small optical control pulse energy. The currently demonstrated TOAD can be switched with 0.8 pJ, and the SMZ with 11 pJ. We still can reduce the control pulse energy by optimizing and employing other nonlinear optical materials. The most critical problem associated with a slow recovery time of the resonance nonlinearities has been solved by a special geometrical location of a nonlinear optical element in the Sagnac interferometer, and two control pulses to do independent on and off switching operation for the Mach-Zehnder. We demonstrated a 10 ps switching window by counter-propagating the control and data pulses in the Mach-Zehnder interferometer using 0.65 pJ of control pulse energy. This device is advantageous in its superior rejection capability of the control signal. In terms of the possibility of integration, this device is expected to be a much simpler design than the previously demonstrated systems. Also the utilized optical nonlinear elements are semiconductor optical amplifiers, the data signal can be larger than the input. This may facilitate cascadability and fan-out capability.","PeriodicalId":118150,"journal":{"name":"IEEE Princeton Section Sarnoff Symposium","volume":"1 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":"131512651","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.1995.636758
C. Armiento, P. Melman, E. Bulat, M. Tabasky
Fiber-to-the-Home (FTTH) is considered to be the ultimate approach to delivering services such as video, high-speed data etc. Deployment of a FTTH network would require widespread use of optoelectronic and optical hardware and thus could provide an application requiring massive volumes of these components. This paper presents an assessment of the optoelectronic component technology required for a FTTH system. It is argued that the performance requirements for this application are rather modest, allowing the use of existing device designs. The challenge for the optoelertronics industry is to reduce the cost and improve the device reliability to a level where a FTTH network becomes practical to deploy.
{"title":"Challenges for optoelectronic hardware in fiber-to-the home systems","authors":"C. Armiento, P. Melman, E. Bulat, M. Tabasky","doi":"10.1109/SARNOF.1995.636758","DOIUrl":"https://doi.org/10.1109/SARNOF.1995.636758","url":null,"abstract":"Fiber-to-the-Home (FTTH) is considered to be the ultimate approach to delivering services such as video, high-speed data etc. Deployment of a FTTH network would require widespread use of optoelectronic and optical hardware and thus could provide an application requiring massive volumes of these components. This paper presents an assessment of the optoelectronic component technology required for a FTTH system. It is argued that the performance requirements for this application are rather modest, allowing the use of existing device designs. The challenge for the optoelertronics industry is to reduce the cost and improve the device reliability to a level where a FTTH network becomes practical to deploy.","PeriodicalId":118150,"journal":{"name":"IEEE Princeton Section Sarnoff Symposium","volume":"1 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":"125419558","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.1995.636775
D. Garbuzov, R. Martinelli, H. Lee, P. York, R. Menna, J. Connolly, S. Narayan, D. Capewell
Continuous and quasi-continuous wave operation of 2.7-μ InGaAsSb/AlGaAsSb multi-quantum-well (MQW) lasers was demonstrated up to a temperature of 234 K (-39°C) and 253 K (-20°C), respectively. These devices were grown by molecular-beam epitaxy (MBE). They tend to operate in a dominant single mode over well defined temperature and current intervals. A comparison of spontaneous emission spectra shows that above threshold the quasi-Fermi level is pinned and that most of the carriers are injected into non-lasing states. This effect leads to a rapid decrease of differential efficiency with increasing temperature.
{"title":"2.7-μm InGaAsSb/AlGaAsSb laser diodes with continuous wave operation up to -39°c","authors":"D. Garbuzov, R. Martinelli, H. Lee, P. York, R. Menna, J. Connolly, S. Narayan, D. Capewell","doi":"10.1109/SARNOF.1995.636775","DOIUrl":"https://doi.org/10.1109/SARNOF.1995.636775","url":null,"abstract":"Continuous and quasi-continuous wave operation of 2.7-μ InGaAsSb/AlGaAsSb multi-quantum-well (MQW) lasers was demonstrated up to a temperature of 234 K (-39°C) and 253 K (-20°C), respectively. These devices were grown by molecular-beam epitaxy (MBE). They tend to operate in a dominant single mode over well defined temperature and current intervals. A comparison of spontaneous emission spectra shows that above threshold the quasi-Fermi level is pinned and that most of the carriers are injected into non-lasing states. This effect leads to a rapid decrease of differential efficiency with increasing temperature.","PeriodicalId":118150,"journal":{"name":"IEEE Princeton Section Sarnoff Symposium","volume":"1 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":"130323298","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.1995.636617
D.M. Poticny
Personal Communications Services (PCS) is a hot topic of discussion in the communication industry at this time. Many people and businesses are trying to determine the best way to participate in this industry. This includes existing telecommunications companies, cable television companies, power companies, small businesses, banks, entrepreneurs, and many people who would like to capitalize on the next "miracle" industry. PCS is viewed as the next major "boom" industry like cable television or the cellular phone industry and an opportunity not to be missed. With all this attention, what exactly is PCS and how will it be accomplished? This paper will discuss the history and build-up to PCS, the radio spectrum that is being auctioned by the government to support PCS, and the challenges facing those people and businesses who enter this business. The first auction is complete but legal issues are not closed. The second and third auctions Will follow. The cellular industry by attracting over 20 million customers has proven the need for mobiltty and personal communications. The challenges facing the new PCS industry will be even greater than for the cellular industry. We firmly believe that there is substantial unfilled demand and that the new PCS entrants will find new services and ways to attract customers. There is untapped potential in data, video, and competition with existing communications services. The risks are great but spectrum, like land, is limited so the rewards will be greater.
{"title":"The PCS Spectrum Auction","authors":"D.M. Poticny","doi":"10.1109/SARNOF.1995.636617","DOIUrl":"https://doi.org/10.1109/SARNOF.1995.636617","url":null,"abstract":"Personal Communications Services (PCS) is a hot topic of discussion in the communication industry at this time. Many people and businesses are trying to determine the best way to participate in this industry. This includes existing telecommunications companies, cable television companies, power companies, small businesses, banks, entrepreneurs, and many people who would like to capitalize on the next \"miracle\" industry. PCS is viewed as the next major \"boom\" industry like cable television or the cellular phone industry and an opportunity not to be missed. With all this attention, what exactly is PCS and how will it be accomplished? This paper will discuss the history and build-up to PCS, the radio spectrum that is being auctioned by the government to support PCS, and the challenges facing those people and businesses who enter this business. The first auction is complete but legal issues are not closed. The second and third auctions Will follow. The cellular industry by attracting over 20 million customers has proven the need for mobiltty and personal communications. The challenges facing the new PCS industry will be even greater than for the cellular industry. We firmly believe that there is substantial unfilled demand and that the new PCS entrants will find new services and ways to attract customers. There is untapped potential in data, video, and competition with existing communications services. The risks are great but spectrum, like land, is limited so the rewards will be greater.","PeriodicalId":118150,"journal":{"name":"IEEE Princeton Section Sarnoff Symposium","volume":"65 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":"115380159","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.1995.636770
R. Qiu, I. Lu
The effect of chirality on the modal dispersion characteristics of optical fibers is investigated. We can tune the chiral admittance to design transmission links with zero dispersion or frequency equalizers with some specific frequency characteristics.
{"title":"Dispersion properties of chiral optical fibers","authors":"R. Qiu, I. Lu","doi":"10.1109/SARNOF.1995.636770","DOIUrl":"https://doi.org/10.1109/SARNOF.1995.636770","url":null,"abstract":"The effect of chirality on the modal dispersion characteristics of optical fibers is investigated. We can tune the chiral admittance to design transmission links with zero dispersion or frequency equalizers with some specific frequency characteristics.","PeriodicalId":118150,"journal":{"name":"IEEE Princeton Section Sarnoff Symposium","volume":"2 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":"128909251","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.1995.636760
J. Damask, J. Ferrera, V. Wong
The integrated resonant channel-dropping filter was first proposed by H.A. Haus in 1991 for use in wavelength-division multiplexed (WDM) fiber-optic communication systems. The function of the filter is to spatially separate, or "drop," just one channel from a WDM bit, stream without terminating or otherwise disturbing the remaining channels. The WDM bit stream is carried along the center rib waveguide. Only that channel, or wavelength band, that excites the two side-coupled quarter-wave shifted distributed Bragg reflector (QWS-DBR) resonators is removed from the bus to the left-most waveguide. The remaining channels do not excite the resonators and therefore travel through undisturbed. The action of dropping a single channel from the bus can be reversed to create a narrow-band channel-adding filter. The ability to add or drop a single channel from the entire WDM bit stream augments the repertoire of functions that are available to the WDM system architect. There are three critical optical parameters that must be properly interrelated during design and controlled during fabrication to build a channel-dropping filter having specific spectral characteristics. The three parameters are the grating strength, the evanescent waveguide-waveguide coupling strength, and the phase-velocity mismatch between the resonators and the bus. While e-beam and x-ray lithographies are used to control the length and width dimensions to the order of 10 nm, so too must the vertical dimensions be controlled to the order of 10 nm. This requires accurate control of film thicknesses and etch depths. To the extent that all of the dimensions and materials indices cannot be controlled to the requisite tolerance, a trimming technique is required.
{"title":"Overcoming obstacles to design and fabricate integrated resonant channel-dropping filters","authors":"J. Damask, J. Ferrera, V. Wong","doi":"10.1109/SARNOF.1995.636760","DOIUrl":"https://doi.org/10.1109/SARNOF.1995.636760","url":null,"abstract":"The integrated resonant channel-dropping filter was first proposed by H.A. Haus in 1991 for use in wavelength-division multiplexed (WDM) fiber-optic communication systems. The function of the filter is to spatially separate, or \"drop,\" just one channel from a WDM bit, stream without terminating or otherwise disturbing the remaining channels. The WDM bit stream is carried along the center rib waveguide. Only that channel, or wavelength band, that excites the two side-coupled quarter-wave shifted distributed Bragg reflector (QWS-DBR) resonators is removed from the bus to the left-most waveguide. The remaining channels do not excite the resonators and therefore travel through undisturbed. The action of dropping a single channel from the bus can be reversed to create a narrow-band channel-adding filter. The ability to add or drop a single channel from the entire WDM bit stream augments the repertoire of functions that are available to the WDM system architect. There are three critical optical parameters that must be properly interrelated during design and controlled during fabrication to build a channel-dropping filter having specific spectral characteristics. The three parameters are the grating strength, the evanescent waveguide-waveguide coupling strength, and the phase-velocity mismatch between the resonators and the bus. While e-beam and x-ray lithographies are used to control the length and width dimensions to the order of 10 nm, so too must the vertical dimensions be controlled to the order of 10 nm. This requires accurate control of film thicknesses and etch depths. To the extent that all of the dimensions and materials indices cannot be controlled to the requisite tolerance, a trimming technique is required.","PeriodicalId":118150,"journal":{"name":"IEEE Princeton Section Sarnoff Symposium","volume":"22 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":"126652174","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.1995.636613
O. J. Benjamin
The wireless technology trend is in the direction of being the communications device of choice. Data communications will be more highly used and valued in this medium. Video will continue to be concentrated in broadcast applications and voice traffic will grow as people talk everywhere. The opportunities to apply technology will be great and diverse. This will be reason for carehl selection and planning. Wireless technology will fbel the growth of electronics technology over the next decade.
{"title":"Trends in wireless technology","authors":"O. J. Benjamin","doi":"10.1109/SARNOF.1995.636613","DOIUrl":"https://doi.org/10.1109/SARNOF.1995.636613","url":null,"abstract":"The wireless technology trend is in the direction of being the communications device of choice. Data communications will be more highly used and valued in this medium. Video will continue to be concentrated in broadcast applications and voice traffic will grow as people talk everywhere. The opportunities to apply technology will be great and diverse. This will be reason for carehl selection and planning. Wireless technology will fbel the growth of electronics technology over the next decade.","PeriodicalId":118150,"journal":{"name":"IEEE Princeton Section Sarnoff Symposium","volume":"55 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":"127020940","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.1995.636740
R. Linke, R. Macdonald, G. Devlin, T. Thio, J. Chadi
Photorefractive materials have often been proposed as optical storage as well as optical interconnection media but attempts to build practical systems have been hindered by fundamental limitations of the materials themselves. Recently we have reported a new class of local photorefractive materials based on the properties of deep electron traps known as DX centers which occur in some doped compound semiconductors. These materials overcome many of the problems associated with the conventional materials showing 30 times larger refractive index changes, 60 times better sensitivity to exposing light, grating-period independent sensitivity, and an absence of erasure which normally occurs during multiple-grating exposures in conventional photorefractive materials. The price of all of these advantages is, at least for the present, that the effect in the new materials is persistent only at cryogenic temperatures. Work is underway to identify materials exhibiting these properties at room temperature.
{"title":"A new class of optical materials for holographic storage and beam steering","authors":"R. Linke, R. Macdonald, G. Devlin, T. Thio, J. Chadi","doi":"10.1109/SARNOF.1995.636740","DOIUrl":"https://doi.org/10.1109/SARNOF.1995.636740","url":null,"abstract":"Photorefractive materials have often been proposed as optical storage as well as optical interconnection media but attempts to build practical systems have been hindered by fundamental limitations of the materials themselves. Recently we have reported a new class of local photorefractive materials based on the properties of deep electron traps known as DX centers which occur in some doped compound semiconductors. These materials overcome many of the problems associated with the conventional materials showing 30 times larger refractive index changes, 60 times better sensitivity to exposing light, grating-period independent sensitivity, and an absence of erasure which normally occurs during multiple-grating exposures in conventional photorefractive materials. The price of all of these advantages is, at least for the present, that the effect in the new materials is persistent only at cryogenic temperatures. Work is underway to identify materials exhibiting these properties at room temperature.","PeriodicalId":118150,"journal":{"name":"IEEE Princeton Section Sarnoff Symposium","volume":"123 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":"115555624","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：