JPS6344210B2 - - Google Patents
Info
- Publication number
- JPS6344210B2 JPS6344210B2 JP57032758A JP3275882A JPS6344210B2 JP S6344210 B2 JPS6344210 B2 JP S6344210B2 JP 57032758 A JP57032758 A JP 57032758A JP 3275882 A JP3275882 A JP 3275882A JP S6344210 B2 JPS6344210 B2 JP S6344210B2
- Authority
- JP
- Japan
- Prior art keywords
- light
- local oscillation
- optical
- light receiving
- output
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 230000003287 optical effect Effects 0.000 claims description 26
- 238000001514 detection method Methods 0.000 claims description 13
- 230000010355 oscillation Effects 0.000 description 25
- 239000013307 optical fiber Substances 0.000 description 6
- 230000005540 biological transmission Effects 0.000 description 5
- 239000004065 semiconductor Substances 0.000 description 5
- 238000010586 diagram Methods 0.000 description 4
- 239000000654 additive Substances 0.000 description 2
- 230000000996 additive effect Effects 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 230000006866 deterioration Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 230000035945 sensitivity Effects 0.000 description 2
- 239000000758 substrate Substances 0.000 description 2
- 238000003786 synthesis reaction Methods 0.000 description 2
- 230000002194 synthesizing effect Effects 0.000 description 2
- 238000002834 transmittance Methods 0.000 description 2
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
- 239000010936 titanium Substances 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
- H04B10/60—Receivers
-
- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F2/00—Demodulating light; Transferring the modulation of modulated light; Frequency-changing of light
- G02F2/002—Demodulating light; Transferring the modulation of modulated light; Frequency-changing of light using optical mixing
Landscapes
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- General Physics & Mathematics (AREA)
- Nonlinear Science (AREA)
- Optics & Photonics (AREA)
- Optical Communication System (AREA)
Description
【発明の詳細な説明】
この発明は光ヘテロダイン検波、または光ホモ
ダイン検波光通信システムにおける光合成、検波
装置に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical synthesis and detection device in an optical heterodyne detection or optical homodyne detection optical communication system.
光通信、特に光フアイバ通信における光ヘテロ
ダイン、光ホモダイン検波方式は、その高光受信
感度の故に長中継間隔伝送を可能にする方式とし
て注目されている。ここの方式の受信部における
問題点のひとつに、信号光と局部発振光を合わせ
る合波回路での分岐損失発生の問題がある。この
合波回路として例えばハーフミラーを用いて両光
を合波する場合、ハーフミラーによつて光ビーム
が２分されるので両光に対して少なくとも3dB
（50％）の分岐損失が生じており、これらの分岐
損失はそのままＳ／Ｎの劣化、すなわち光受信感
度の劣化につながるという欠点があつた。 Optical heterodyne and optical homodyne detection systems in optical communications, particularly optical fiber communications, are attracting attention as systems that enable long repeat interval transmission due to their high optical reception sensitivity. One of the problems in the receiving section of this method is that branching loss occurs in the multiplexing circuit that combines the signal light and the local oscillation light. When combining both lights using a half mirror as this multiplexing circuit, for example, the half mirror splits the light beam into two, so it is at least 3 dB for both lights.
(50%) branching loss occurs, and these branching losses directly lead to deterioration of the S/N ratio, that is, deterioration of optical reception sensitivity.
従来この対策として、ミラーの透過率を大きく
して信号光に対する分岐損失を小さくする一方、
その分だけ局部発振光に対して大きくなつた分岐
岐損失を局部発振光源の高出力化で補うことが考
えられてきた。しかしその場合、局部発振光源の
高出力化は装置の大形化、光源の信頼性の低下等
をもたらすという欠点が生じていた。特に半導体
レーザを局部発振光源として使う場合、20ｍＷ以
上の出力が要求されることになるが、実際この出
力で信頼性を保証するのは容易ではない。 Conventionally, as a countermeasure to this problem, the transmittance of the mirror is increased to reduce branching loss for the signal light, while
Consideration has been given to compensating for the increased branching and branching loss with respect to locally oscillated light by increasing the output of the locally oscillated light source. However, in this case, increasing the output of the local oscillation light source has the disadvantage that the device becomes larger and the reliability of the light source decreases. In particular, when using a semiconductor laser as a local oscillation light source, an output of 20 mW or more is required, but it is not easy to guarantee reliability at this output.
本発明の目的はこのような欠点を除き、合波回
路の信号光に対する、分岐損失を実効的に小さく
するとともに、局部発振光源の高出力化があまり
必要でない光ヘテロダイン・ホモダイン検波装置
を提供することにある。 An object of the present invention is to eliminate such drawbacks, to provide an optical heterodyne/homodyne detection device that effectively reduces the branching loss for signal light in a multiplexing circuit, and that does not require much increase in the output of the local oscillation light source. There is a particular thing.
この発明によれば、第１、第２の入射端と第
１、第２の出射端を有し、前記第１、第２の入射
端からの入射光が、それぞれ前記第１、第２の出
射端におよそ１：１の比で分岐された出射する方
向性結合器と、前記第１の入射端から信号光を、
前記第２の入射端から局部発振光をそれぞれ入射
することにより前記第１、第２の出射端から得ら
れる第１、第２の合波光をそれぞれ受光して電気
信号に変換する第１、第２の受光部と、この第
１、第２の受光部からの前記電気信号を合成する
合成部を含む光ヘテロダイン・ホモダイン検波装
置が得られる。 According to this invention, the invention has first and second input ends and first and second output ends, and the incident light from the first and second input ends is transmitted to the first and second input ends, respectively. an output directional coupler branched at a ratio of approximately 1:1 to an output end, and a signal light from the first input end;
First and second beams receiving the first and second combined lights obtained from the first and second output ends by respectively inputting the local oscillation light from the second input end and converting them into electrical signals. An optical heterodyne/homodyne detection device including two light receiving sections and a synthesizing section for synthesizing the electrical signals from the first and second light receiving sections is obtained.
本発明の光ヘテロダイン・ホモダイン検波装置
は方向性結合器（合波回路）で合波される信号
光、局部発振光の内、従来損失分とされていた光
成分についても合波、受光を行ない、その結果得
られた電気信号を、従来有効分とされていた光成
分から得た電気信号に加え合成するものである。
この場合両電気信号の位相が合つていると信号成
分については電圧相加則が、受光部で発生する雑
音については電力相加則が成り立つので、合成し
ない場合に比べＳ／Ｎが最大3dB改善される。こ
のため信号光が合波回路で受ける分岐損失を実効
的に零にできるとともに、局部発振光源の高出力
化もあまり必要でない光ヘテロダイン・ホモダイ
ン検波装置が得られる。次に図面を用いて本発明
について詳しく説明する。 The optical heterodyne/homodyne detection device of the present invention multiplexes and receives optical components that were conventionally considered to be losses among the signal light and local oscillation light that are multiplexed by a directional coupler (multiplexing circuit). The resulting electrical signal is added to and synthesized with the electrical signal obtained from the optical component, which has conventionally been considered an effective component.
In this case, if the phases of both electrical signals match, the voltage additive law holds true for the signal component, and the power additive law holds true for the noise generated in the light receiving section, so the S/N improves by up to 3 dB compared to the case where they are not combined. be done. Therefore, an optical heterodyne/homodyne detection device can be obtained in which the branching loss that the signal light undergoes in the multiplexing circuit can be effectively reduced to zero, and in which it is not necessary to increase the output of the local oscillation light source. Next, the present invention will be explained in detail using the drawings.
第１図は本発明の第１の実施例を説明するため
の構成図である。この実施例では方向性結合器１
はハーフミラー２で構成されている。伝送路３を
出射した信号光４は、第１のレンズ５でほぼ平行
光線に変換されて第１の入射端６からハーフミラ
ー２に入射し、第１、第２の信号光７，８に２分
される。一方信号光４とはf0だけ周波数が異なる
局部発振光９は、半導体レーザよりなる局部発振
光源１０から出射されて第２のレンズ１１でほぼ
平行光に変換される。そして第２の入射端１２か
らハーフミラー２に入射して第１、第２の局部発
振光１３，１４に２分される。信号光４と局部発
振光９のビーム径や光路を調整することにより、
第１の信号光７と第１の局部発振光１３、第２の
信号光８と第２の局部発振光１４が合波され、第
１、第２の合波光２３，２４となる。第１、第２
の合波光２３，２４は第１、第２の出射端１５，
１６を通つてそれぞれ第１、第２の受光部１７，
１８に入射する。第１、第２の受光部１７，１８
はフオトダイオードや増幅器等で構成されてお
り、合波された各光ビームからヘテロダイン検波
により周波数f0の第１、第２の中間周波出力１
９，２０を電気信号の形で出力する。第１、第２
の中間周波出力１９，２０は位相を合わされて合
成部２１で電気的に合成され、中間周波出力２２
となる。なお、位相の調整は第１、第２の受光部
１７，１８と合成部２１をつなぐ導線の長さを変
えて行なつた。 FIG. 1 is a configuration diagram for explaining a first embodiment of the present invention. In this embodiment, the directional coupler 1
is composed of a half mirror 2. The signal light 4 emitted from the transmission line 3 is converted into a substantially parallel light beam by the first lens 5, enters the half mirror 2 from the first input end 6, and becomes the first and second signal light beams 7 and 8. Divided into two. On the other hand, local oscillation light 9 having a frequency different from that of signal light 4 by f 0 is emitted from a local oscillation light source 10 made of a semiconductor laser, and is converted into substantially parallel light by a second lens 11 . Then, the light enters the half mirror 2 from the second incident end 12 and is split into first and second locally oscillated lights 13 and 14. By adjusting the beam diameter and optical path of the signal light 4 and the local oscillation light 9,
The first signal light 7 and the first locally oscillated light 13 and the second signal light 8 and the second locally oscillated light 14 are combined to become first and second combined lights 23 and 24. 1st, 2nd
The combined light beams 23 and 24 are transmitted to the first and second output ends 15,
16 through the first and second light receiving sections 17,
18. First and second light receiving sections 17 and 18
is composed of photodiodes, amplifiers, etc., and generates first and second intermediate frequency outputs 1 at frequency f 0 by heterodyne detection from each combined optical beam.
9 and 20 are output in the form of electrical signals. 1st, 2nd
The intermediate frequency outputs 19 and 20 of
becomes. Incidentally, the phase was adjusted by changing the length of the conducting wire connecting the first and second light receiving sections 17, 18 and the combining section 21.
次に本実施例の効果を説明する。まず、第１の
実施例において信号光４の光パワーをPsとする。
また光ヘテロダイン検波を有効に行なうのに必要
な第１、第２の局部発振光１３，１４の光パワー
がPL、従つて局部発振光９の光パワーが2PLであ
るとする。PLは伝送速度数百Mb／ｓの光フアイ
バ通信の場合で５ｍＷ程度である。なお、方向性
結合器１、第１、第２のレンズ５，１１等におい
て、吸収、散乱等で生じる過剰損失は小さいので
無視する。また、信号光に対して分岐損失がない
合波回路を仮定し、受光部にPSの信号光とPLの
局部発振光が入射した場合、中間周波出力のＳ／
Ｎがａになるとする。ところが、第１の実施例で
は、第１、第２の受光部１７，１８には分岐損失
のために1/2PSになつた第１、第２の信号光７，
８と、PLの第１、第２の局部発振光１３，１４
とがそれぞれ合波されて入射するので、第１、第
２の中間周波出力１９，２０のＳ／Ｎはそれぞれ
ａ／２となる。しかし合成部２１で第１、第２の
中間周波出力１９，２０が位相を合わせて合波さ
れると、信号成分に関しては電圧相加の原理が、
雑音成分に関しては電力相加の原理が適用される
のでＳ／Ｎが２倍に改善されてａとなる。 Next, the effects of this embodiment will be explained. First, in the first embodiment, the optical power of the signal light 4 is assumed to be Ps .
Further, it is assumed that the optical power of the first and second locally oscillated lights 13 and 14 necessary for effective optical heterodyne detection is P L , and therefore the optical power of the locally oscillated light 9 is 2 P L . P L is about 5 mW in the case of optical fiber communication with a transmission rate of several hundred Mb/s. Note that excess loss caused by absorption, scattering, etc. in the directional coupler 1, the first and second lenses 5, 11, etc. is small and will be ignored. Furthermore, assuming a multiplexing circuit with no branching loss for the signal light, when the P S signal light and the P L local oscillation light are incident on the light receiving section, the intermediate frequency output S/
Suppose that N becomes a. However, in the first embodiment, the first and second signal lights 7, which have become 1/2P S due to branching loss, are sent to the first and second light receiving sections 17, 18.
8, and the first and second local oscillation lights 13 and 14 of P L
Since the signals are multiplexed and input, the S/N of the first and second intermediate frequency outputs 19 and 20 is a/2, respectively. However, when the first and second intermediate frequency outputs 19 and 20 are combined in phase in the combining section 21, the principle of voltage addition is applied to the signal components.
As for the noise component, since the principle of power addition is applied, the S/N is improved twice to a.
結局、局部発振光５の光パワーを必要量PLの
２倍にするだけで信号光４に対する合波回路の分
岐損失が零の場合と同じＳ／Ｎが得られることに
なる。 In the end, by simply increasing the optical power of the local oscillation light 5 to twice the required amount PL , the same S/N ratio as when the branching loss of the multiplexing circuit for the signal light 4 is zero can be obtained.
従来例では、ハーフミラーを使う場合、Ｓ／Ｎ
をａ／２にしかできなかつた。またミラーの透過
率を例えば80％にしてＳ／Ｎを0.8aにしようとす
る場合、局部発振光に対するミラーの分岐損失が
大きくなるので、受光部への局部発振光入力を
PL得るためには５・PLの局部発振光源出力が必
要になつた。５・PLは約25ｍＷに相当し、現状
の半導体レーザでこの値を安定に得るのは簡単で
はない。これに対し本発明ではＳ／Ｎをａにでき
て、しかも局部発振光源の出力は２・PL、約10
ｍＷで良い等、大幅な改善が得られる。 In the conventional example, when using a half mirror, the S/N
could only be reduced to a/2. Furthermore, when trying to set the S/N to 0.8a by setting the transmittance of the mirror to 80%, for example, the branching loss of the mirror for the local oscillation light will increase, so the input of the local oscillation light to the light receiving section will be reduced.
In order to obtain P L , a local oscillation light source output of 5 P L is required. 5.P L corresponds to approximately 25 mW, and it is not easy to stably obtain this value with current semiconductor lasers. In contrast, in the present invention, the S/N can be reduced to a, and the output of the local oscillation light source is 2·P L , approximately 10
Significant improvements can be obtained, such as requiring only mW.
第２図は本発明の第２の実施例を説明するため
の構成図である。第２の実施例においては方向性
結合器１は光IC化したものを、第１、第２の受
光部１７，１８、合成部２１は電気IC化したも
のを使用した所に特徴がある。 FIG. 2 is a configuration diagram for explaining a second embodiment of the present invention. The second embodiment is characterized in that the directional coupler 1 is an optical IC, and the first and second light receiving sections 17, 18, and the combining section 21 are electrical ICs.
方向性結合器１はガラス基板３０と、そのガラ
ス基板３０上にチタンを拡散して作つた第１、第
２の導波路３１，３２とから構成されている。伝
送路３からの信号光４（図示せず）は第１の入射
端６から直接第１の導波路３１に結合する。結合
した信号４は近接部３３で約1/2の光パワーが第
２の導波路に分岐され、第２の信号光８（図示せ
ず）となつて第２の出射端１６に向う。残り1/2
の光パワーは第１の信号光７（図示せず）として
第１の出射端１５に向う。一方半導体レーザより
なる局部発振光源１０からの局部発振光９（図示
せず）は光フアイバ３４で伝送されて、第２の入
射端１２から第２の導波部３２に結合する。局部
発振光９は信号光４の場合と同様に近接部３３で
第１、第２の局部発振光１３，１４（図示せず）
に２分される。第１の局部発振光１３は第１の導
波路３１を第１の出射端１５の方向に伝送されな
がら第１の信号光７と合波される。第２の局部発
振光１４も同様に第２の導波路３２を第２の出射
端１６の方向に伝送されながら第２の信号光８と
合波される。第１、第２の受光部７，１８および
合成部２１はハイブリッドIC３５にしたもので、
第１、第２の受光部１７，１８をそれぞれ第１、
第２の出射端１５，１６に近接してある。第１の
実施例の場合と同様に合成部２１から中間周波出
力２２が得られる。 The directional coupler 1 includes a glass substrate 30 and first and second waveguides 31 and 32 made by diffusing titanium onto the glass substrate 30. Signal light 4 (not shown) from the transmission line 3 is directly coupled to the first waveguide 31 from the first input end 6 . Approximately 1/2 of the optical power of the combined signal 4 is branched to the second waveguide at the proximal portion 33 and becomes a second signal light 8 (not shown), which is directed toward the second output end 16. 1/2 left
The optical power is directed to the first output end 15 as the first signal light 7 (not shown). On the other hand, local oscillation light 9 (not shown) from a local oscillation light source 10 made of a semiconductor laser is transmitted through an optical fiber 34 and coupled from the second input end 12 to the second waveguide section 32 . The local oscillation light 9 is connected to the first and second local oscillation lights 13 and 14 (not shown) in the vicinity part 33 as in the case of the signal light 4.
It is divided into two parts. The first local oscillation light 13 is multiplexed with the first signal light 7 while being transmitted through the first waveguide 31 in the direction of the first output end 15 . The second locally oscillated light 14 is similarly transmitted through the second waveguide 32 toward the second output end 16 and is multiplexed with the second signal light 8 . The first and second light receiving sections 7 and 18 and the combining section 21 are hybrid ICs 35,
The first and second light receiving sections 17 and 18 are respectively
It is located close to the second output ends 15 and 16. As in the case of the first embodiment, an intermediate frequency output 22 is obtained from the combining section 21.
なお、伝送路３および光フアイバ３４は直線偏
光保存性の光フアイバであることが望ましい。 Note that the transmission line 3 and the optical fiber 34 are preferably linear polarization-preserving optical fibers.
第２の実施例の効果も第１の実施例の場合と同
様である。 The effects of the second embodiment are also similar to those of the first embodiment.
本発明においては上記実施例の他にもさまざま
な変形が考えられる。方向性結合器１としては、
ハーフミラー２や導波路を用いるもの以外にも、
２入力、２出力の４端子方向性結合器であれば、
さまざまなものが使用可能である。方向性結合器
１の第１、第２の出射端１５，１６と第１、第２
の受光部１７，１８の間は光フアイバ等で結合さ
せても良い。また第１、第２の受光部１７，１８
と合成部２１の間に超音波遅延線等の適当な遅延
線を挿入して、第１、第２の中間周波出力１９，
２０の位相合わせを行なつても良い。局部発振光
源１０としては当然半導体レーザ以外のレーザ光
源を使用しても良い。方向性結合器１の分岐比は
基本的には１：１であることが望ましいが、１：
１から多少ずれても良い。また合成は第１、第２
の中間周波出力１９，２０を検波後、ベースバン
ド帯域で行なつても良い。なお本発明は局部発振
光９の周波数を信号光４の周波数と等しくしたホ
モダイン検波方式にも同様に適用できる。 In the present invention, various modifications can be made in addition to the above-mentioned embodiments. As the directional coupler 1,
In addition to those using half mirror 2 and waveguides,
If it is a 4-terminal directional coupler with 2 inputs and 2 outputs,
Various types are available. The first and second output ends 15 and 16 of the directional coupler 1 and the first and second
The light receiving sections 17 and 18 may be coupled by an optical fiber or the like. In addition, the first and second light receiving sections 17 and 18
An appropriate delay line such as an ultrasonic delay line is inserted between the synthesizer 21 and the first and second intermediate frequency outputs 19,
20 phase alignments may be performed. Naturally, a laser light source other than a semiconductor laser may be used as the local oscillation light source 10. Basically, it is desirable that the branching ratio of the directional coupler 1 is 1:1;
It may be slightly different from 1. Also, the synthesis is the first and second
After detecting the intermediate frequency outputs 19 and 20 of , the detection may be performed in the baseband band. Note that the present invention can be similarly applied to a homodyne detection method in which the frequency of the local oscillation light 9 is made equal to the frequency of the signal light 4.
第１図は本発明の第１の実施例を示す構成図、
第２図は同じく第２の実施例を示す構成図であ
る。
なお図において、１……方向性結合器、６，１
２……方向性結合器１の第１、第２の入射端、１
５，１６……方向性結合器１の第１、第２の出射
端、４……信号光、９……局部発振光、２３，２
４……第１、第２の合波光、１７，１８……第
１、第２の受光部、２１……合成部である。
FIG. 1 is a configuration diagram showing a first embodiment of the present invention,
FIG. 2 is a configuration diagram showing a second embodiment as well. In the figure, 1... directional coupler, 6, 1
2...First and second input ends of the directional coupler 1, 1
5, 16...First and second output ends of the directional coupler 1, 4...Signal light, 9...Local oscillation light, 23,2
4...first and second combined light, 17, 18...first and second light receiving sections, 21...combining section.
Claims (1)
有し、前記第１、第２の入射端からの入射光が、
それぞれ前記第１、第２の出射端におよそ１：１
の比で分岐されて出射する方向性結合器と、前記
第１の入射端から信号光を、前記第２の入射端か
ら局部発振光をそれぞれ入射することにより前記
第１、第２の出射端から得られる第１、第２の合
波光をそれぞれ受光して電気信号に変換する第
１、第２の受光部と、この第１、第２の受光部か
らの前記電気信号を合成する合成部を含む光ヘテ
ロダイン・ホモダイン検波装置。1 has first and second input ends and first and second output ends, and the incident light from the first and second input ends is
Approximately 1:1 to the first and second emission ends, respectively.
a directional coupler that branches and emits signals at a ratio of first and second light receiving sections that respectively receive the first and second combined lights obtained from the light receiving section and convert them into electrical signals; and a combining section that synthesizes the electrical signals from the first and second light receiving sections. Optical heterodyne/homodyne detection device including.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP57032758A JPS58149025A (en) | 1982-03-02 | 1982-03-02 | Optical heterodyne-homodyne detector |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP57032758A JPS58149025A (en) | 1982-03-02 | 1982-03-02 | Optical heterodyne-homodyne detector |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS58149025A JPS58149025A (en) | 1983-09-05 |
| JPS6344210B2 true JPS6344210B2 (en) | 1988-09-02 |
Family
ID=12367736
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP57032758A Granted JPS58149025A (en) | 1982-03-02 | 1982-03-02 | Optical heterodyne-homodyne detector |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS58149025A (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS59135646A (en) * | 1983-01-24 | 1984-08-03 | Canon Inc | System for reproducing magnetooptic information |
| GB2172164B (en) * | 1985-03-07 | 1989-02-22 | Stc Plc | Balanced coherent receiver |
| US4697284A (en) * | 1986-05-08 | 1987-09-29 | American Telephone And Telegraph Company, At&T Bell Laboratories | Single-photodiode optical heterodyne mixers |
| US4723316A (en) * | 1986-05-08 | 1988-02-02 | American Telephone & Telegraph Company, At&T Bell Laboratories | Polarization independent coherent optical heterodyne receivers |
| NL8801490A (en) * | 1988-06-10 | 1990-01-02 | Philips Nv | DEVICE FOR OPTICAL HETERODYNE DETECTION AND INTEGRATED OPTICAL COMPONENT SUITABLE FOR APPLICATION IN SUCH A DEVICE. |
-
1982
- 1982-03-02 JP JP57032758A patent/JPS58149025A/en active Granted
Non-Patent Citations (2)
| Title |
|---|
| THE INSTITUTE OF RADIO ENGINEERS INC. =1961 * |
| THE INSTITUTE OF RADIO ENGINEERS INC. =1962 * |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS58149025A (en) | 1983-09-05 |
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