JPS6223841B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical switch using a specially processed prism and its prism.

In a conventional optical switch, two incident beams A and B consisting of an ordinary ray and an extraordinary ray each having orthogonal polarization planes are passed through polarizing prisms 1 and 2, respectively, as shown in Fig. 1A. The two light beams are guided to an optical crystal 3 having effects, etc., and the crystal 3 is electrically controlled from the outside as shown at 4.The two light beams are then guided to an analyzing prism 5, and a beam is outputted to the output side 6 by controlling the crystal 3. Output either A or B. Further, as shown in FIG. By controlling the optical crystal 3 by guiding the beam to the analyzing prism 5 which has a different output direction, either the output beam C or the output beam D is output.

In both A and B above, since the polarizing prism 1 having orthogonal polarization planes is used, this polarizing prism has the disadvantage of causing a loss of 3 dB.

The present invention aims to eliminate the above-mentioned drawbacks, and the first invention is a prism for realizing an optical switch without using a polarizer. The prism has an inclined reflective surface formed at one diagonal corner of the prism having birefringence, and has first and second rays each consisting of an ordinary ray and an extraordinary ray each having a plane of polarization perpendicular to an incident surface other than the reflective surface. A light beam is made incident, and one of the ordinary rays is reflected by the reflecting surface, and the extraordinary ray of the first incident beam, the ordinary ray of the second incident beam, and the The extraordinary rays of the two incident beams and the ordinary rays of the first beam are respectively combined to output the first and second output beams.

This will be explained in detail in Fig. 2. The same reference numerals as in Fig. 1 indicate the same parts, and 7 in Fig. 2 has birefringence that has been subjected to the above-mentioned special processing to form a reflective surface at the diagonal corner. The prism is, for example, a calcite prism, which is conventionally used as a beam separator, and two diagonal reflective surfaces 8 and 9 are machined and polished, respectively, and mirror surfaces are formed by reflective coating or metal vapor deposition. Reference numerals 10 and 11 are non-processed portions, that is, non-reflective portions at other diagonal corners, and transmit the light beam.

When the first incident beam A enters the non-reflecting surface, that is, the transmitting surface 10 of the prism 7, it is split into an extraordinary ray A ₂ of A and an ordinary ray A ₁ of A, which are then directly transmitted from the opposing non-reflecting surface 11 as A ₂ and A ₁ , respectively. Emits light. The second incident beam B is incident on the non-reflecting surface 10 of the prism 7 and
It is divided into the ordinary ray _B1 of B and the extraordinary ray _B2 of B. This medium extraordinary ray B ₂ exits as it is from the non-reflecting surface 11 and is combined with the ordinary ray A ₁ of the first incident beam to become the first outgoing beam D. The ordinary ray B ₁ is reflected by one diagonal corner inclined reflecting surface 9 and then reflected by another diagonal corner inclined reflecting surface 8.
It is re-reflected at , exits from the non-reflective surface 11, and is combined with the extraordinary ray _A2 of the first incident beam A to become a second outgoing beam C. The positions of incidence of the first incident beam A and the second incident beam B on the incident surface may be reversed from the above case.

The above two incident beams with orthogonal polarization planes are separated into four beams within the prism, and any beam among the four beams is reflected within the prism to form two output beams. It is desirable to adjust the angle of inclination of the reflecting surface, the length and area of the inclined surface, etc. so as to combine them.

FIG. 3 shows a 2-input, 2-output optical switch constructed using the method of synthesizing light beams having a polarization plane using a specially processed prism according to the present invention, and shows the same reference numerals as in FIGS. 1 and 2. 7 and 7' indicate the same part, and 7 and 7' are birefringent prisms, such as calcite prisms, which are placed in front and behind the optical crystal, and the first incident beams A and 7' have polarization planes perpendicular to the prism 7, respectively. Second incident beam B
When the first incident beam A is made incident, the first incident beam A is separated into two beams, the plane of polarization is rotated by the optical crystal 3, and the first incident beam A is combined by the prism 7' again.
It is output to the output C or the second output D. The same applies to the second incident beam B. 2 inputs above, 2
Since no polarizer is used in the output optical switch, no loss occurs due to it.

The method of synthesizing light beams having polarization planes using a specially processed prism of the present invention does not use any polarizers, so there is no loss due to polarizers, and light can be synthesized extremely efficiently.

[Brief explanation of the drawing]

Figure 1 A and B are explanatory diagrams of an optical switch for a light beam with a polarization plane using a conventional polarizer, and Figure 2 is a synthesis of a light beam with a polarization plane using a specially processed prism according to the present invention. FIG. 3 is a front view showing an embodiment of the method, and is an explanatory diagram of an optical switch using a prism used in the present invention. 1 and 2 are polarizers, 3 is an optical crystal, 4 is an external control means, 5 is an analyzer, 6 is an output, 7 and 7' are calcite prisms that form reflective surfaces, 8, 8', 9,
9' is a diagonal corner inclined reflecting surface, 10 and 11 are incident surfaces excluding the reflecting surface, A and B are incident beams, and C and D are output beams.

Claims (1)

[Claims] 1. An optical crystal 3 having an external control means 4 is sandwiched therebetween, and inclined reflecting surfaces 8, 9, 8', and 9' are added to one diagonal corner of a prism having birefringence before and after the optical crystal 3. The formed prisms 7 and 7' are arranged to form an ordinary ray and an extraordinary ray, each having a plane of polarization perpendicular to the incident surface 10 excluding the reflecting surface of the prism 7 disposed in front of the optical crystal 3. The first and second light beams A, A ₁ , A ₂ , B, B ₁ , B ₂ are incident, and after passing through the optical crystal 3, the first and second light beams are Outgoing beam C,
_{The first output beam} and An optical switch characterized in that the output position of the second output beam is switched. 2 Regarding the prism 7 formed by adding inclined reflective surfaces 8 and 9 to one diagonal corner of a prism having birefringence, ordinary rays and extraordinary rays having orthogonal polarization planes from the incident surface 10 excluding the reflective surface First and second light beams A, A ₁ , A ₂ , B, B ₁ ,
B ₂ is made incident, one of the ordinary rays B ₁ is reflected by the reflecting surfaces 8 and 9, and an extraordinary ray of the first incident beam is made from the exit surface 11 excluding the reflecting surface of the opposing surface.
A ₂ and the ordinary ray B ₁ of the second incident beam, , the extraordinary ray B ₂ of the second incident beam and the ordinary ray A ₁ of the first incident beam are combined to form the first and second output beams C,
A prism for an optical switch, characterized in that A ₂ , B ₁ , D, A ₁ , and B ₂ are emitted.