JPS59226326A - Optical function device - Google Patents

Abstract

PURPOSE:To obtain an optical function device which performs easily fundamental optical logic operations by connecting nonlinear interferometer units, where a nonlinear medium whose refractive index is dependent upon the intensity of light is inserted into a triangular optical ring constituted with prescribed elements, through anoptical isolator to constitute the device. CONSTITUTION:In the unit constitution of the nonlinear optical interferometer, an input light 1, a transmitted light 2, a reflected light 3, a beam splitter 4 where the light intensity distribution rate is not 50%, 100% reflective mirrors 5 and 6, and a nonlinear medium 7 whose refractive index is changed in proportional to the intensity of light are provided. The device is constituted with one stage of the nonlinear optical interferometer unit where the nonlinear medium 7 is inserted into the triangular optical ring or these nonlinear optical interferometer units are connected in many stages through optical isolators to constitute the device.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical functional device that is small in size and operates at high speed.

The present invention is characterized in that a nonlinear optical ring interferometer is constructed using an optical nonlinear medium whose refractive index changes depending on the light intensity, and its purpose is to realize a high-speed optical logic element.

FIG. 1 is an embodiment of the present invention, showing the configuration of a nonlinear optical interferometer unit. In Figure 1, 1 indicates input light 2 and 8 are transmitted light and reflected light, respectively, and 4 indicates a light intensity distribution ratio of 50.
The beam splitter 5.6 is 100% main reflection, and the beam splitter 7 is an optical nonlinear medium whose refractive index changes in proportion to the light intensity (for example, an optical power-(Kerr) effect medium such as AS or GaAS).

Semiconductor materials such as InSb and S soil, both of which are media with third-order nonlinear susceptibility.

If the beam splitter's optical electric field amplitude reflectance is r and its transmittance is t, then the electric field amplitude of transmitted light is E. ut, t and the electric field amplitude E of the reflected light. ut, r becomes 0 Eout, t − (tgeXp(-ioF) − r”eX
l)(-ioB))Ein(1)Eout, r -rt
CeXp(-SuF)+8Xp(-iOB))E, IH
(2) Here, yF and rice are expressed by the following equation (8) and (
4) is the phase amount given by formula.

J'y −l() ” IB (t g +
2r 2 nl “in l”
(8) 91iB-1(, + $2 (2t" + r"
)l "in l" (4) Here, pIo is the phase amount during one pass of the light through the optical interferometer forming a ring, Da2 is a constant representing the magnitude of nonlinearity of the medium, and Ein is is the incident light electric field amplitude.

Therefore, the transmitted light and reflected light intensities are respectively expressed as follows.

pout, t −(1−2r2t”(1+oosβ(r
g-t2)Pin))Pin(5)”Out, r −2
r2t"(1+cosβ(r"-t")Pin)Pin
) Pi, (6) where P. ut, t are transmitted light intensity'
"out, r is the reflected light intensity, Pin is the incident light intensity, β is the nonlinear refractive index coefficient of the medium, and β-,12S (S
: Expressed in beam cross section. r −t −0
, 5, from equation (5) s (a), "out, r
−”in t Pout, t ”-0, and the optical ring acts as a mere 100% reflective mirror, and nonlinear interference does not occur. However, in the case of r”vt”, the output light is , will have an oscillatory solution.

Physically, when the two divided light beams return to the beam splitter, their relative phases are (5) # (6)
As expressed by term 008 in the equation, it changes depending on the input light intensity, and corresponds to an in-phase and anti-phase relationship occurring alternately.

In Fig. 2, InSb with a thickness of 200 μm is used as a nonlinear medium, the input light wavelength is 5 μm, and the beam cross section is 1-1-1r 0.
．． 6, shows the input/output characteristics when t" -0.4. In this case, it is β-0.8 radian 777LW, and as is clear from Fig. 2, the change in output light intensity with respect to light input intensity is negative. There exists a region with a slope of .This characteristic can be easily applied to optical inverters (NOT circuits) and waveform conversion.

Figure 8 shows β-0,8 rad/mW, rB-0,8(t
-0,2) Optical inverter characteristics [Figure 8 (
a)] and waveform conversion (sine wave→pulse) characteristics [in Fig. 3].

FIG. 4 is an embodiment of an apparatus in which the nonlinear optical interferometer units are connected in multiple stages via an optical isolator 8. Assuming that the number of stages at which the inverter characteristics become remarkable due to multi-stage design is N, the input/output characteristics for N-1 to N-5 are shown in FIG. β
-0.8 radian/? 7LW.

r"-0,6, t-0,4. As the number of stages increases, the slope of the curve becomes steeper, and it can be easily applied to optical logic circuits.

(a) AND using the circuit shown in FIG. 4 in FIG.

(b) OR, (c) NAND, (d) NOR
An example of the operation and a truth table are shown. In the case of (a), Do bias of light "in", i) q is 0<Pin, DC<Pi,.

Binding, input pulse peak value Pi,b is Pi,a/2
＜ Pi, b＜ Pi, c / 2.
If two optical pulses are input as the input shown in FIG. 1, a logical operation as shown in the truth table shown in FIG. 6(a) is possible.

For FIG. 6(b) to (1), “in, DC”
``By selecting irb as shown, each logical operation is possible.

As explained above, the optical functional device of the present invention has an extremely simple configuration, and has the following functions: N, OT, AND, OR, NAN.
D.

Basic optical logic operations such as NOR can be easily performed. It has the advantage of having a large beam diameter and being able to perform batch parallel processing of image information in real time. The response time is determined by the speed of change in the refractive index of the optical nonlinear medium, and is usually thought to be picoseconds, so ultra-high-speed processing can be achieved.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an embodiment of the device of the present invention, FIG. 2 is a diagram of optical input/output characteristics of the device of the present invention, and FIG. , FIG. 8(b) is a diagram showing the waveform conversion (sine wave → pulse) characteristics of the device of the present invention, and FIG. 4 is an example diagram of a device in which nonlinear optical interferometer units are connected in multiple stages via optical isolators. , Figure 5 is an input/output characteristic diagram of the multi-stage connection type device, Figure 6 (a), (b),
(C) and (d) are AND and OR, respectively, of two-man optical logic operations using the device of the present invention. It is an example diagram of NAND and NOH. 1...Input light, 2...Transmitted light, 8...Reflected light, 4
... Beam splitter, 5, 6... 100% main reflection, 7... Optical nonlinear refractive index medium, 9... Optical isolator. (AI & N 4'7no, tgh αw) J'mon 'nose A' (N) 7'7'D, (rad ρ go [niu (home)

Claims (1)

[Claims] 1 Beam splitter with a light intensity distribution ratio other than 50% and 2
A nonlinear optical interferometer unit is constructed in one stage by inserting an optical nonlinear medium whose refractive index depends on the light intensity into a triangular optical ring composed of two reflecting mirrors, or the nonlinear optical interference An optical functional device characterized in that it is configured by connecting measuring units in multiple stages via optical isolators.